How to clean battery compartment?

July 18, 2020 at 17:07:30
Specs: several
Alkaline batteries throughout.

I bought a fairly nice flashlight about three years ago.
The body looks like titanium to me, but the packaging
just called it "advanced alloy".

Maybe the problem is that I put Duracell batteries in it
last time, while the flashlight was made by Energizer...

It last worked three or four weeks ago. Yesterday I
bought some new batteries (It takes 2 AA).

When I opened the battery compartment, the bottom
battery was stuck in the end cap. The negative end
had leaked and gunked up the inside of the end cap.
It is like scale in plumbing from hard water. Scrubbing
it with a green Scotchbrite pad isn't getting it clean.

Is there a way to clean it without destroyng it?

Or as usual, do I have to destroy what I clean?

-- Jeff, in Minneapolis

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July 18, 2020 at 20:21:14
You'd be surprised how many "fake Chinese batteries" get sent into this country. You could try a paste of baking soda and water to neutralize the acid and polish off the contacts after drying with a reasonably stiff rotary-tool wire brush. If the corrosion is serious enough, you may have to replace the terminals.

"Channeling the spirit of jboy..."

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July 18, 2020 at 22:04:50
There's some stuff meant to clean car battery terminals and connections. It's in a spray can. I think it's basically the baking soda and water that T-R-A recommended, but you can also give that a try.

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July 18, 2020 at 23:15:06
If you think I need to neutralize the acid, that means you
think there is acid present. Is that correct? Even though
it is an alkaline battery? And even after all my scrubbing?

Whatever the chemical composition of the "gunk", it does
look something like the result of being attacked by acid.
Or maybe a strong alkali. But does it actually still contain
acid? (Or alkali?)

Actually, the "gunk" looks a lot like a splotch of dried baking
soda solution.

The distal phalange (I always wanted to say that) of my little
finger fits easily into the end cap. No other finger fits. In other
words, not many tools would fit in it. Especially not power tools.
Come to think of it, though, a whole mess of new tools just
showed up in the workshop! Somebody who moved into the
building recently must have donated them. Maybe there is a
Dremel tool in there somewhere, with a teeny-tiny wire brush.

I'm sure I'm going to destroy my flashlight before I get it clean.

-- Jeff, in Minneapolis

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July 19, 2020 at 01:26:56
I never gave any thought to the chemical makeup of the battery leakage. Maybe I should--I don't know. After applying the cleaning stuff I always use an old toothbrush to scrub the contacts and then I tear off a small piece of a green scratch pad and try to work it over the contacts to remove the discoloration from them. Lastly I use damp Q-tips to remove the cleaning residue.

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July 19, 2020 at 01:33:35
Even the big brand names leakproof batteries leak in time.

A Drexel or similar tool might get the stuff off.

Soaking the area with water - no descaled additives etc. - might help loosen it. And a final rinse out with methylated spirits after cleaning with the Drexel type attachments and water would be useful too.

Occurs to me that vinegar might help, but again wash out afterwards with H2O and meths?

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July 19, 2020 at 02:49:04
As it happens, there are at least two Dremel tools in the workshop,
and they seem to be available for anyone to use. But the couple of
tiny wire brushes I found are too big to go into the flashlight's end
cap. There are two tiny sanding cylinders, but they aren't quite tiny
enough. Without the abrasive grit on them, I think they would slide
right into the tube. With the grit, an obvious impossibility. And they
wouldn't be able to get the bottom, where the contact is.

There is a stone-like tool that would fit, but it is the wrong shape to
get into the corners, and I don't know what that type of tool is for or
how to use it. Although I've known for decades that they exist.

I've got several different cleaning products, and there are more in the
workshop, but I'm dubious that any of them will work on the "gunk".

I'll just mention that I am NOT going to be mixing chlorine bleach
with anything else, but I do have bleach.

Also 91% isopropyl alcohol (the virus of the year prefers 70%),
3% hydrogen peroxide, and 100% acetone. As well as Lime A-way
and a Liquid Plumber-type drain cleaner which is mostly bleach.
And vinegar. I already used baking soda. I could try the vinegar
and baking soda together, but aside from making a mini geyser,
I doubt it would do anything useful.

-- Jeff, in Minneapolis

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July 19, 2020 at 04:22:58
There are various size and length wire brush attachments for the Drexel type tool. Some are very slim...

The big forest/river company has assorted makes.

There is a common warning from several users... Wear eye protection and be aware they spray metals particles all over the place; and they will embed in clothing. So take steps to safeguard against this . A pair of overalls - which later wash separately?

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July 19, 2020 at 09:21:53
Thank you, trvlr ! All very helpful advice!

"In order to clean his flashlight, he had to destroy it."

As far as I can see, the end cap is just a nicely-shaped
and nicely-finished hunk of metal, with the current from
the battery being conducted by the entire body, so
hacking away at it shouldn't impair its functioning at all.

Edit to add: There is a rubber-like O-ring on the end cap,
so I can't immerse it in caustic chemicals, but it is on the
outside of the threads, separated from the gunk which
needs to go.

-- Jeff, in Minneapolis

message edited by Jeff Root

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July 19, 2020 at 12:57:19
Are you sure BOTH end don't unscrew? Mag brand do.

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July 19, 2020 at 14:52:51
re' OtH and Mag brands...

So do most of the other brands (I've had in the past) - both ends are removable; albeit a snug/tight fit but removable.

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July 19, 2020 at 16:06:44
It is only the negative end of the rear battery that leaked, so
only the inside of the end cap got mucked up. But yes, the
front end screws off, too.

And it is a bit lucky that only the end got gunked, because I had
the flashlight standing front-end down, so if the gunk was really
runny, it would have run down and wrecked the whole thing.

To be excessively clear, when I said that the distal phalange of
my little finger fits inside the end cap, I was trying to create an
image of both the inside diameter and the depth: It is as deep
as the end segment of my little finger. Deeper than it is wide by
several millimeters. So, no toothbrushes, unless they make
toothbrushes for mice...

-- Jeff, in Minneapolis

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July 19, 2020 at 16:29:05
You might find an Oral B electric toothbrush head will fit and help; especially if you have an Oral B toothbrush kit?

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