Introduction: Safe Handling & Decontamination Procedures for COVID-19

About: I helped start Instructables, previously worked in biotech and academic research labs, and have a degree in biology from MIT. Currently head of Product helping young startups at Alchemist Accelerator, previous…

I originally wrote this document for a friend with an immunocompromised family member, and have since used the same procedures at our house to help reduce risk for elderly high-risk family members.

While the chance of infection via virus-contaminated surfaces may be low, if you have friends and family who are extremely high-risk due to age, immune issues, or other health complications that increase the chance of death from COVID-19, that risk may still feel significant. These are reasonable practices you can adopt to reduce that risk. You can decide how strictly you choose to follow these procedures based on your family's risk profile and risk tolerance.

Why me? I helped start Instructables, used to design protocols for sterile technique in biology labs and biopharmaceutical manufacturing facilities, and have a biology degree from MIT. Based on my experience, I have adapted these instructions so they can hopefully be followed by a tired, untrained human.

This document is a work in progress, and we're constantly getting better information about the coronavirus that causes COVID-19. I’ll be updating with references, more examples, clarifications, and new information as it comes to my attention. Please feel free to ask questions in the comments.

In the steps below, I'll address:

  1. Assumptions (what these procedures assume both about the virus, and about your household)
  2. Disinfection options (how to kill it)
  3. Avoiding droplet contamination when out
  4. Re-entry home after potential contamination (removing droplets shed by others)
  5. Delivery handling for packages, mail, groceries, and restaurant food
  6. Socialization and activities
  7. General questions
  8. Generally useful links

Step 1: Assumptions

Since this is a new virus, we're learning more about it on the fly. Here are the assumptions I've made about the virus (with links to my references, which I'll update when newer info shows up) and about your household, which are necessary to make sure these procedures are useful.

  1. Virus is transmitted via surfaces and actively-projected droplets, not aerosols (except in confined spaces and specific healthcare situations), though it may linger in the air up to 3 hours in poorly-ventilated areas.
  2. Virus dies in 24h on paper and cardboard, 72h (3 days) on metal and plastic at room temperature without additional measures, and the amount of virus drops exponentially as time goes by.
  3. No members of the family already have/are shedding the virus1. Every time someone leaves the house or touches anything that might be exposed is an opportunity to introduce infection.
  4. Individuals can shed virus before they display symptoms, and some individuals (especially children and younger adults) may be infected without displaying any symptoms during the entire course of their infection.

Additional reference to paper on virus survival:

1 Quarantine of infected family members is outside the scope of this Instructable, as I don't have expertise in this area. Check out this CDC page on what to do if you are sick, or caring for someone who is sick with COVID-19.

Step 2: Disinfection Options

There are lots of chemicals accepted for commercial disinfection of the virus, but here are the most reasonable for use at home. See more at the CDC site.

  1. Soap and water – scrub and rinse thoroughly to disrupt virus’s lipid bilayer. Minimum 20 seconds for hand washing.
  2. >70% alcohol (isopropanol or ethanol) – apply liquid or gel evenly and allow to air dry; rub into hands evenly.
  3. 10% dilute bleach (>0.1% Sodium hypochlorite) – apply evenly and allow to air dry
  4. Note: Benzalkonium chloride and other chemicals are not as effective but can greatly decrease the number of viruses on a surface.

Note that not all things safe for use on surfaces should be used on skin or food products! Be kind to your skin, your hands will be washed a lot - use lotion as needed.

Additional reference:

Step 3: Avoiding Droplet Contamination When Outside Your Home

Since the virus is transmitted through droplets, you want to avoid contracting the virus yourself (inhaling droplets or touching them and transferring to your mucous membranes) or getting droplets on your skin or belongings.

  1. Wear a mask if it’s feasible. Homemade cloth masks can block >50% as much as a proper surgical mask. (see image for stats per mask type)
  2. Don’t touch your face, especially mucous membranes (eyes, mouth, nose)
  3. Maintain >6’ buffer from others whenever possible
  4. STAY AWAY from anyone who is coughing or sneezing
  5. Keep track of anything you touch with your hands and/or body (car seat, steering wheel, phone, wallet, purse, keys, mail, bags, boxes, door handles, etc) and disinfect upon return home
  6. Disinfect hands when you get into car if possible
  7. Conduct re-entry procedure upon return home

Step 4: Re-entry Home After Potential Contamination

This procedure helps you remove any droplets potentially shed onto your body, clothes, or belongings by others while you were outside your home. This will make sure you don't spread virus to the interior of your home, or to other people inside.

  1. Wash or sanitize hands as soon as possible without tracking through the house
  2. Leave footwear at the door.
  3. Remove all outerwear immediately upon entry, and put directly into the washer. Wash as usual with laundry soap and warm water. If you can’t launder clothing, quarantine it for at least 24 hours, longer (72h/3days) for slippery surfaces like leather, plastic, or rubber.
  4. Wash hands and/or take shower depending on level of potential exposure. Use soap and water to clean exposed surfaces, including shampoo to wash hair.
  5. Be sure to disinfect faucet handles, door knobs, elevator buttons, etc that may have been touched with dirty hands, as well as your keys, cell phone, purse, etc.
  6. Use paper towels for drying hands upon re-entry. Change cloth towels and hand towels daily. Do not share cloth towels unless everyone has been isolated in the house for at least a week with no symptoms.

Step 5: Delivery Handling for Packages, Mail, Groceries, and Restaurant Food

If you're staying at home, you'll need to get things delivered to your home. This process presumes the packer or shipper covered the package and/or its contents with virus, and is designed to safely contain and/or kill the virus to avoid contaminating your house and the people inside it.


  1. Have items delivered and left at front door/entryway without proximity/contact
  2. Let items sit in the sun for a bit if feasible as UV is detrimental to the virus (obviously not appropriate for refrigerated/frozen deliveries, or areas where packages are stolen)
  3. If direct handoff is necessary, ask for item to be put down, and retrieve item when the other person has retreated to a distance of >6’.

Boxes, packages, and mail:

  1. If feasible, bring into a secure location and quarantine (leave alone without touching) for >24h (cardboard) or >72h (plastics) before opening as usual. (Wash hands after handling freshly-delivered box, and before touching anything else.)
  2. If opening before quarantine is expired, open box/package, dump contents out onto clean and washable surface without touching contents, dispose of box/package, and wash hands before touching anything else.
  3. Internal contents of package may be touched >24h (paper or cardboard) or >72h (plastics or metals) after shipping date (last time they were potentially handled by humans), or you may disinfect the contents if they must be used before quarantine time has expired. Disinfect any door knobs, faucet handles, trash lids, or other areas you may have touched.

Grocery deliveries:

  1. Bring bags inside, set on an open washable surface (usually the floor), and wash hands before continuing.
  2. Get out clean bags for food quarantine. I use paper grocery bags from previous deliveries that are outside >24h paper items quarantine window.
  3. Designate one “clean” hand and one “dirty” hand. Use the “dirty” hand to transfer food items to clean “quarantine” bags, separating items into different bags if they are stored in refrigerator/freezer/room temperature, while you manipulate clean “quarantine” bags with your clean hand.
    • Room temperature items: sort items into clean "quarantine" bags and set aside for 24-72 hours depending on surface type. If you need to use items earlier, disinfect the outside of the items or dump the contents onto a clean surface without touching contents and dispose of the package. Wash hands.
    • Refrigerated items: studies on other related viruses suggest the virus may be able to survive for a longer period in the refrigerator, so a 3-day quarantine in the refrigerator may be insufficient. Here's how to further minimize your exposure to virus from refrigerated food. Be sure to wash and cook your foods thoroughly as usual.
      • Items packaged at the factory: disinfect the outside of containers. Wash hands, and transfer to the refrigerator. No further quarantine required. (Examples: milk, cheese, tortillas, eggs, hot dogs, etc)
      • Items packaged at the grocery: disinfect the outside of packages or transfer contents into clean containers without touching contents, and dispose of packaging. Wash hands, and transfer to the refrigerator. You may choose to apply a further quarantine period inside the refrigerator. (Examples: meat from the meat counter or in plastic-wrapped trays, cut and wrapped cheese, etc)
      • Bagged or loose SOLID fruits and vegetables that will be peeled: dump contents directly into a large bowl and discard packaging. Wash with mild soap and water, rinse thoroughly, and air dry. Wash hands, and transfer to the refrigerator. No further quarantine required. Alternatively, dump contents out of plastic packaging directly into clean "quarantine" bags, wash hands, and leave at room temperature for >24h before transferring to refrigerator, no further quarantine required.
      • Bagged, boxed, or loose SOFT fruits and vegetables that will not be peeled: dump contents out of plastic packaging directly into clean "quarantine" bags, wash hands, and leave on counter for as long as possible (preferably >24h) before transferring to the refrigerator. You may choose to apply a further quarantine period inside the refrigerator.
      • Salad bars, pre-made sushi, sliced deli items: don't buy these things during a pandemic. Avoid foods that are recently handled by humans but can't be disinfected, quarantined at room temperature, or cooked/re-cooked before you eat them.
    • Frozen items: Since the virus may be able to survive for months in the freezer, we must disinfect (or safely remove) the outside packaging, not just quarantine these items.
      • Disinfect the exterior of frozen items before placing them in the freezer.
      • Alternatively remove external packaging and dump contents directly onto a clean surface (if there's an internal package, say for frozen pizza) or into a clean container without touching contents, and dispose of packaging; wash hands and transfer item to freezer.
  4. Put empty “dirty” bags (the ones that were just delivered) aside where they won't be touched for >24h if paper, >72h if plastic. Disinfect area they sat on during transfer. Wash hands.
  5. Disinfect any door knobs, faucet handles, cabinets, refrigerator doors, trash lids, or other areas you may have touched.
  6. After the 24-72h wait period, all quarantined items and bags should be safe – sort and put things away as normal. Be sure to wash and cook foods thoroughly as usual.
  7. NOTE: if you have an especially vulnerable person in your household, you may choose to avoid raw fruits and vegetables that won't be cooked before eating.

Restaurant food deliveries: (best to order cooked food only)

  1. Bring bags inside, set on an open washable surface (probably floor), and wash hands before continuing.
  2. Remove food containers from outer bag, and set on a clean, open, washable surface (probably the counter). Put outer bag in the trash, and wash hands before continuing.
  3. Get out clean containers (plates, bowls, Tupperware, etc) and a fork or spoon, and set on clean surface a bit away from the food containers.
  4. Designate a “clean” hand and a “dirty” hand. Use “dirty” hand to pick up the food container, and use the fork or spoon in the “clean” hand to scoop the food into your clean container. Throw the dirty container into the trash and wash hands.
  5. Reheat food in microwave, oven, or stovetop before eating.
  6. Disinfect any door knobs, faucet handles, cabinets, refrigerator doors, trash lids, or other areas you may have touched.
  7. Disinfect all surfaces that the restaurant and food containers touched. Wash hands.

Step 6: Socialization and Activities

Don’t socialize or do anything that brings you into contact with other humans from outside your home if you can avoid it. If you must go out, follow the reentry protocol. Exceptions may be made for others who have FULLY self-quarantined for minimum 2 weeks without symptoms, but you must absolutely trust their adherence to protocol because you’re adding them to your quarantine bubble. Remember that people can be infectious/shed virus at least 24h before showing symptoms, and some (especially children and younger adults) may never show symptoms despite being infected.

  1. Playdates:NO Children are much more likely to be asymptomatic virus spreaders, and can’t be trusted to follow proper infection protocols. Socialize via video chat.
  2. Dining out: NO Get delivery of ingredients or COOKED foods if necessary, and follow delivery protocol above.
  3. Dining with friends at their/your house: NO. As stated above, interacting with friends means you’re adding them to your quarantine bubble. Only do this if they’ve fully self-quarantined for >2 weeks without symptoms, and you fully trust their quarantine measures as stated above. Video chat with friends over dinner instead.
  4. Playgrounds/Parks: NO. Children touch play structures with all their fluids, which may persist on metal and plastics for many days. Play structures are never washed (rain doesn’t count) so this is a high-risk behavior. Find other ways for children to have active play inside or in an isolated outdoor space.
  5. Hikes, Walks, and Nature: Yes! Don’t touch surfaces that others may have passed near or touched, and stay far away from others. Best practice is to select an outdoor space or hiking trail that is very low-traffic to avoid seeing any other humans. Fresh air and sun are good for the immune system, and a walk or hike through an empty area is a great way to get outside safely. Re-entry protocol not required in most cases.
  6. Your yard: Yes! Don’t touch surfaces that others may have passed near or touched (mailbox, walkway, doorbell) and stay far away from others. Fresh air and sun are good for the immune system, UV disinfects, and a private yard is a great way to get outside safely. Re-entry protocol not required in most cases.
  7. Gyms: NO. If you must, disinfect the equipment before use and make sure to stay as far away from others as possible – more than 6’ as people breathing heavily can spread droplets more widely. Ask the gym to keep doors and windows open to maximize air circulation. Tie hair out of face, don’t touch your face, and wash your hands frequently. Follow re-entry protocol upon return home.
  8. Dog walking: Yes! Like other walks and hikes, select a low-traffic area to avoid seeing other humans, and don’t touch surfaces that others may have passed near or touched. Don’t pet other people’s dogs, as they may have droplets in their fur. Don’t allow your dog to socialize with other humans or their dogs, as this may transfer droplets to their fur, and require modification of the decontamination protocol for your dog. Skip this unless you really want to haul your dog into the shower with you for a shampoo.

Step 7: General Questions

This is hard to think about, do you have an analogy to help?

Think of the virus as wet paint. If you touch a surface covered in wet paint, you can get it on your hands/jacket, then everything you touch or bump into can get wet paint on it as well. The solution is to either wait until the paint dries (ie the virus is dead) before touching, or to touch the wet paint only as much as you have to then immediately wash the wet paint off yourself and anything you touched with your paint-covered hands.

What if my Amazon package/grocery delivery was packed by someone with COVID-19?
The processes described above assume the packer or shipper has covered the package and/or its contents in virus, so if you follow these steps the virus will be safely contained upon entry to your house, and dead by the time the quarantine period is up. Then you can safely eat your food/open your package.

Can you tell me more about food, restaurants, and grocery shopping?

Check out this great piece on food safety from J. Kenji López-Alt on Serious Eats. My only quibble is that he relies heavily on the fact that we haven’t yet traced a case to some of these sources (food, fecal contamination, etc) so emphasizes that the risk is probably quite low. However, for those who are immunocompromised or otherwise at high risk of death from COVID-19 that risk can be too high. It’s easy enough to put some or all of these measures in place, and reduce even a low risk of contracting the virus much closer to zero.

Is this just a giant over-reaction?

If you or a loved one are immunocompromised, elderly, have a lung condition, are undergoing cancer treatment, are diabetic or pre-diabetic, or have issues with your heart or other organs, you are much higher risk of death from COVID-19 according to the CDC. Our knowledge of this new coronavirus is evolving (as is the virus itself) and If there's even a small risk of infection you may choose to eliminate it. This is a simple set of procedures to follow that can reduce the risk of contamination, and you can decide how much to apply to your household.

Step 8: Generally Useful Links

There are lots of confusing and incorrect things circulating about on the coronavirus, so always refer to reliable sources like:

The World Health Organization including their daily Situation Report

The Centers for Disease Control and Prevention