How to remove corrosion or battery leakage from device terminals - Page 1
Forum section: electronics / beginners

author: RiRaRi
author_rank: Regular Contributor
timestamp: September 02, 2025, 04:25:00 pm
content: I work with a lot of cameras and portable radio receivers, and I often encounter corroded battery terminals or signs of battery leakage. In cases of severe corrosion, sanding the metal may be the only solution. However, in the case shown in the attached photos, I don’t believe the metal has been damaged. I hope there is a proper procedure to safely remove this residue without harming the device.Please review the photos and advise on the best cleaning methods.

author: TimFox
author_rank: Super Contributor
timestamp: September 02, 2025, 04:31:31 pm
content: Have you tried an old-style typewriter eraser (mildly abrasive with a narrow tip)?

author: BeBuLamar
author_rank: Super Contributor
timestamp: September 02, 2025, 05:06:07 pm
content: Vinegar or somewhat more concentrated acetic acid.

author: themadhippy
author_rank: Super Contributor
timestamp: September 02, 2025, 05:16:20 pm
content: get some bicarb of soda in there. scrub it in with a tooth brush and rinse with vinager followed by water

author: Ian.M
author_rank: Super Contributor
timestamp: September 02, 2025, 05:23:15 pm
content: Yep. Scrubbing with a toothbrush with white vinegar + a single drop of dish detergent for wetting should clean off most of the crud. You'll need to rinse really thoroughly with hot water, then get it reasonably dry and flush with IPA to ensure there is no acetic acid residue.Formic acid is even more effective at removing this sort of corrosion. Its commonly sold as kettle descaler (but avoid the citric acid ones) Use full strength as above, but take care to avoid skin contact.Note that the above use of weak acids is for leakage fromZinc carbon (aka 'heavy duty'), andAlkaline primary cells and NiCd and NiMH rechargables which all have alkaline electrolyte. Not recommended for leakage from other battery technologies. e.g. for Lead Acid, the electrolyte is Sulphuric acid which must be neutralised, typically with bicarbonate of soda, but that does sweet F.A. (other than acting as a mild abrasive if you use a lot of it in powder form and scrub vigorously) for alkaline electrolyte leakage. If you do need a paste abrasive, metal polish or toothpaste would be a far better choice!Edit: themadhippy is probably right to recommend bicarbonate of soda for initial neutralisation of Zinc carbon dry cell or 'heavy duty' dry cell electrolyte leakage as their ammonium chloride or zinc chloride electrolytes are somewhat acidic. However the bulk of the work of re-dissolving the corrosion salts will be done by the vinegar rinse.

author: metrologist
author_rank: Super Contributor
timestamp: September 02, 2025, 06:26:50 pm
content: I'll hit it with a toothbrush and vinegar, then scrub bicarb and water to clean, then rinse clean. IPA is good for a final rinse, then dry.An re-plating nickel or tin is not that hard.

author: Analog Kid
author_rank: Super Contributor
timestamp: September 02, 2025, 07:33:25 pm
content: Yes; vinegar (white is fine) followed by a water rinse.I've never worried about terminals that lost some of their plating due to corrosion; just check them from time to time for more corrosion and remove if needed.

author: metrologist
author_rank: Super Contributor
timestamp: September 02, 2025, 07:38:15 pm
content: and dialectic geese

author: Analog Kid
author_rank: Super Contributor
timestamp: September 02, 2025, 08:20:12 pm
content: Quote from: metrologist on September 02, 2025, 07:38:15 pmHonk honk--Marx & Engels--honk honk.

author: metrologist
author_rank: Super Contributor
timestamp: September 02, 2025, 08:59:59 pm
content: yeah, the schmoo for your electrical terminals.

author: Analog Kid
author_rank: Super Contributor
timestamp: September 03, 2025, 12:05:15 am
content: I was always taught to put grease--any kind (except maybe bacon grease!) on your battery terminals after snugging them up.

author: wasyoungonce
author_rank: Frequent Contributor
timestamp: September 03, 2025, 04:29:59 am
content: aliexpress and fleabay do sell replacement battery contact terminals. It's a nightmare search but you will find them, or something close enough. If you reuse those....they may need re-plating

author: RiRaRi
author_rank: Regular Contributor
timestamp: September 03, 2025, 03:42:15 pm
content: Thank you all for replies. I let the terminals to soak in white vinegar for 10 minutes and results are very good. All green goo is gone but there is still some rust left. What to do as a second step? Any way to remove this brown rust which has "eaten" the metal. Thanks

author: MrAl
author_rank: Super Contributor
timestamp: September 03, 2025, 04:35:23 pm
content: Hi,After they are completely clean, you can apply a thin coat of dielectric grease to help prevent future corrosion.

author: Analog Kid
author_rank: Super Contributor
timestamp: September 03, 2025, 06:41:50 pm
content: Quote from: RiRaRi on September 03, 2025, 03:42:15 pmA quick rub with fine sandpaper (400/600) or steel wool ought to take care of that.Like I wrote earlier, don't obsess over trying to replate those areas; just keep them clean each time you change the battery and you'll be fine.

author: Ian.M
author_rank: Super Contributor
timestamp: September 03, 2025, 06:58:45 pm
content: You could try any non-hazardous rust remover gel to get the rust out of the pits, though you will probably need abrasives as suggested by Analog Kid to get a clean enough surface at the contact points. Don't use a phosphoric acid rust remover or a rust converter because they will leave an insulating film on the surface. After derusting, washing and drying with hot air or IPA, you must immediately coat the terminals with a thin smear of petroleum jelly or dielectric grease to protect them from atmospheric moisture, which will otherwise quickly flash-rust them.

author: Terry Bites
author_rank: Super Contributor
timestamp: September 04, 2025, 11:12:45 am
content: Yes. Rinsing is essential. The iron and nickel acetate salts are corrosive in thier own right.I'm an oxalic acid fan boy, probably because I found a 5kg tub.

author: Ian.M
author_rank: Super Contributor
timestamp: September 04, 2025, 01:25:16 pm
content: Oxalic acid is great at removing rust, especially rust stains, but is not for the slap-dashed. Appropriate PPE and sufficient care to avoid any contact is essential as it wont just give you acid burns, its also a poison.

author: Stray Electron
author_rank: Super Contributor
timestamp: September 04, 2025, 08:41:38 pm
content: Hands down the best thing that I've found for that type of corrosion is some of the CLR or Lime Away bathroom cleaner that's sold in the US super markets. It's mainly Phosphoric Acid but it doesn't seem to affect the surrounding metal and only attacks the corrosion. Just apply some to the corrosion and let it sit for 1/2 hour and then scrub it off with an old tooth brush and then rinse with clean water and dry thoroughly. You may need to repeat a 2nd time.

author: kite31
author_rank: Regular Contributor
timestamp: September 04, 2025, 10:21:12 pm
content: Mostly I use the finest grade of wet-and-dry paper which will do the job in a reasonable time without undue damage.The length of your string may vary.

author: bostonman
author_rank: Super Contributor
timestamp: September 05, 2025, 01:33:47 pm
content: If the battery leaked, usually it ruins plastic unless you catch it early enough.Usually lemon juice works well (with a toothbrush to gently scrub the terminals) and I keep a container just for this reason.

author: metrologist
author_rank: Super Contributor
timestamp: September 05, 2025, 04:28:43 pm
content: I believe lemon juice usually has some sugar

author: Gyro
author_rank: Super Contributor
timestamp: September 05, 2025, 05:21:33 pm
content: Less so when it comes out of a Lemon. Sugar is water soluble.

author: 5U4GB
author_rank: Super Contributor
timestamp: September 06, 2025, 02:32:59 am
content: Surprised no-one's brought up Deoxit yet, that's supposed to be specifically for cleaning and protecting corroded contacts. It tends to be -ing expensive if you're outside the US which is why I've not tried it myself but comments on it seem to be generally positive.

author: WattsThat
author_rank: Frequent Contributor
timestamp: September 06, 2025, 04:31:46 am
content: Detox-it. Especially the 100% stuff. Great results on battery leakage corrosion. And, yes, it’s F-ing expensive, even within the US. That said, I’ve used the same small bottle for years.

author: ME
author_rank: Frequent Contributor
timestamp: September 06, 2025, 02:00:47 pm
content: sandblast it!.

author: artvandalai
author_rank: Regular Contributor
timestamp: September 07, 2025, 08:02:01 pm
content: CRC 26 spray