One of those chemicals is called 2 butoxyethanol, which is present in most commercial cleaning products, in quantities too small to be listed on the labels. However even at those concentrations it has been shown to be absorbed easily through the skin both from contact and vapors. It is carcinogenic, it affects the kidneys and reproductive health (and if female reproductive health isn't visual enough think "testicular atrophy"). Have I convinced you? DIY!
Some people swear by using a solution of 50/50 water and vinegar for just about everything. Not only am I not too fond of the smell, but I don't think it works very well either. I tested various recipes I found on the web and finally came up with my own. The first one is great at dissolving grease and is perfectly safe to use on food preparation surfaces: the alcohol evaporates and the only other inedible ingredient it contains is soap, but there is so little of it the spray can be used without the need to rinse. The second can be used to clean your oven (without killing your braincells or endangering your unborn child) AND your toilet. I like using the glass cleaner for ceramic sinks as well as glass and mirrors. The dishwasher detergent can also be used as a scrubbing powder with bleaching power (and without the harmful vapors). Finally the spray for your shower curtains can double as a fruit and vegetable cleaner.
I mentioned this is cheap and it is: however buying all the ingredients the first time you make these will cost more than a single spray bottle of all purpose cleaner. This will be a considerable long term savings, as you can make many many batches with your supplies.
One last word of caution: always label the bottles properly and include a list of the ingredients. These are perfectly safe to use as directed, and they're definitely less toxic than most commercial cleaners but in case of accidental ingestion you still need to be able to tell the poison control center what the product contains. It's a lot easier to check the bottle rather than look up this instructable while your kid is vomiting and 911 is on the line....
Step 1: Spray for food preparation surfaces
1/4 tsp citrus essential oil (orange is my favorite, but any citrus will do)
1 drop (or one gell) of soy lecithin (optional)
1 tbsp rubbing alcohol (optional)
2 tsp citric acid (or 1 1/2 cup distilled vinegar)
2 tbsp liquid castille soap
One empty, clean, 32 oz spray bottle with the label removed.
Whisk together essential oil, lecithin and alcohol in a small bowl. Add citric acid and, if necessary, enough hot water to dissolve the citric acid (alt. instead of citric acid, add vinegar). Mix in the liquid castille soap.
Pour all ingredients into an empty 32 oz spray bottle. Fill bottle to top with warm water and shake vigorously.
Shake the bottle before each use, spray the surface generously and allow it to sit for a few minutes before wiping it off. Most dried-out, encrusted food spill will come right off without any effort.
UPDATE: Since I published this instructable a year ago my recipe has changed a bit. This version is quicker to make and cheaper. The results are just as good.
2 tbsp scented liquid castille soap (so I can omit essential oils)
2 tsp washing soda
1 tsp citric acid
1 drop soy lecithin (OPTIONAL -- it makes the counters silky smooth but don't buy it just for this)
tap water to fill a 32oz spray bottle.
Pour washing soda and optional lecithin directly into your spray bottle, and fill half way up with hot tap water. Close it, shake it, allow the soda to dissolve. Then add liquid castille soap and swish it around gently to combine it without creating an eruption of bubbles. In a separate container mix your citric acid with a cup of hot tap water till it dissolves. You COULD put the citric acid in your spray bottle directly, but then you can expect your mixture to foam up, as the washing soda reacts with the acid, and the soap may turn white and gooey. Even when you dilute the citric acid first, you'll get some bubbling action, but the reaction will be muted. Once things have settled down, add enough cold tap water to top off your spray bottle. You're done.
For problem spots like red wine stains on white formica surfaces, mix together 1 part citric acid with 2 parts baking soda. Sprinkle over the stain, mist with this cleaner (or even plain water) till the powder fizzes, let sit a few minutes and scrub it off.
Notes on ingredients:
I prefer citric acid rather than vinegar because it has no smell and has the same effect: it treats the water, enhancing the performance of the soap and preventing white mineral deposits and streaks. Citric acid is a bit harder to find: in Brooklyn Sahadi's carries it but they call it lemon salt. Kosher grocery stores call it sour salt. Brewing and soapmaking supply stores carry it, and it will cost less there than in grocery stores. If you use distilled water rather than plain old tap water you can skip both the vinegar and the citric acid.
The purpose of the lecithin is to disperse the essential oil in the water -- but is also enhances the performance of the cleaner. Don't ask me why, I don't know. But I tried it with and without, and including lecithin made the cleaner perform better. Plus it makes my Paperstone counters feel silky smooth.
The alcohol's purpose is also to help disperse the oil -- at this concentration it's not going to disinfect anything.
Use liquid castille soap (such as Dr. Bronner's, available at Trader Joe's or at the Vitamin Shop) rather than regular liquid dishwashing soap if you're interested in avoiding the chemicals I mentioned in the intro. Another option is to grate two tablespoons worth of soap off a bar such as Ivory and dissolve it in boiling water.
The citrus essential oil helps dissolve grease -- in addition to making everything smell great. If you like you can combine different oils. Rosemary, for example, is reputed to have antiseptic properties which might be useful in a cleaner.
Washing soda is sodium carbonate, which is more alkaline than sodium bicarbonate (aka baking soda). Including it makes the spray more alkaline, which improves its cleaning potential (more of the splatters in kitchen are acidic -- tomatoes, wine, etc). By including washing soda I no longer need expensive essential oils or the rubbing alcohol. Reducing the number of ingredients also makes the spray faster to make... In NYC washing soda in in the laundry aisle of practically any supermarket. I've heard it can also be found in pool supply stores, sold as "soda ash."