Corroded Maglite




Introduction: Corroded Maglite

About: I miss the days when magazines like Popular Mechanics had all sorts of DIY projects for making and repairing just about everything. I am enjoying posting things I have learned and done since I got my first ...

I had not used this Maglite flashlight for a while. When I tried to use it, the bulb did not illuminate. When I tried to check the batteries, there were signs they were dead and had leaked. There was corrosion and the batteries did not slide out with ease as is usual. The photo shows my Maglite after I used the procedures in this Instructable.

I know Maglites have a warranty. Still, there would be a shipping cost that is more than I want to pay.


  • Sheet metal screw
  • Wood dowel and fine sandpaper
  • Thin brass sheet


  • Pocket knife
  • Drill
  • Screwdriver
  • Pliers (possibly also a vise and a hammer)
  • Scissors

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Step 1: Rap the Flashlight

I rapped the flashlight sharply on a protective surface. One battery moved and slowly came out, but one was very stuck. I did try a thin oil, like WD-40, but it did not loosen the stuck battery.

Step 2: Drill and Add a Screw

I needed a way to pull the stuck battery. I drilled into its center as best I could and inserted a sheet metal screw. The battery was already very dead. I was not concerned about generating heat from a short. First, I tried using a pair of slip joint pliers to pull the battery with my bare hands. It still did not move. I protected the flashlight with a rag and put it into a vise. Then I gripped the sheet metal screw with a pliers so I could use a hammer to loosen the battery and eject it from the open end of the flashlight. Results were not immediate, but I did get the stuck battery out.

Step 3: Scrape Away the Corrosion

A thin blade on a pocket knife can be helpful for scraping away corrosion inside the flashlight. But, it may also be necessary to fold a strip of sandpaper over a wooden dowel rod about the size of the battery diameter and work the sandpaper back and forth to remove corrosion. Scrape corrosion from the end cap shown in the photo as much as possible, especially the small metal tabs that contact the insides of the flashlight barrel.

Step 4: Close, But No Cigar

After removing as much corrosion as possible, the flashlight would light if the end cap was just a little loose. The flashlight was not dependable. Sometimes it did not light at all. Sometimes it lit, but only faintly.

Step 5: Finally, a Solution

It seemed as if the metal tabs on the end cap did not really make good contact with the inside of the flashlight barrel. I have some brass sheet only a couple of thousandths of an inch thick. I cut a strip about 3/16" wide and about 7/8" long with a scissors. I slipped it into the spring on the end cap, and let the ends cover the metal tabs. When I screwed the end cap into the flashlight, it works dependably.

I decided to experiment with aluminum from a soft drink can. See the second photo. The metal strip is a little thicker. I also cut it a little wider and a little shorter. I scraped away the coating on both sides and checked with an electrical meter to be certain good contact is available. The aluminum strip is next to the contact points, not over them. But, it works!

The best would be always to install new batteries before they leak. I now have a prompt on my calendar to replace batteries in the Maglite flashlights we have annually.

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    4 Discussions


    1 year ago

    very good

    Phil B
    Phil B

    Reply 1 year ago

    Thank you. Since posting this, I have also seen a suggestion that alkaline battery corrosion should be neutralized with an acid, like vinegar.


    1 year ago

    A very nice Instructable. Also a reminder that ALL dry-cell batteries eventually leak. (The main difference is that cheaper ones leak sooner.) I know I do not check & change batteries as often as I should. But the other extreme is the practice when I was in the Air Force: remove the batteries if the item probably won't be used in the next 30 days.

    Phil B
    Phil B

    Reply 1 year ago

    Thank you for your comment and for the benefit of your experience. We keep a AA Maglite in a vehicle glove box. It is especially easy to forget about that one.