Sound technical content, curated with aloha by
Ted Mooney, P.E. RET
Pine Beach, NJ

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Cleaning corroded pennies and coins

Q. I have a quart plastic container full of wet black pennies. What is the best and fastest way to shine them up?

Viola Bressan
I am a retired woman with lots of pennies. - Loveland Colorado
December 30, 2021

A. Try ammonium citrate solution (50 gms citric acid ⇦this on eBay or Amazon [affil links] , 1 lit water, add some ammonia ⇦this on eBay or Amazon [affil links] 25%, pH must be 9). Hope it helps and good luck!

Goran Budija
- Cerovski vrh Croatia

Q. I have a large amount of pennies but they got wet and turned black and some are fused together. I tried vinegar ⇦in bulk on eBay or Amazon [affil links] , and a table spoon of salt last night to clean the gunk off of some of my more dirtied up change...it turned my silver a pink color. Any way to reverse this?

Tom Ferguson
- Fremont, Ohio, USA

A. Hi Tom. The pink is probably copper from pennies or the edges of your 'silver' coins. Copper would be unlikely to deposit on silver, but your 'silver' coins are probably cupro-nickel. I'd just spend it a coin at a time and people probably won't object.

Regards,

Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
February 2018

March 22, 2018

I had coins recovered from the ocean. I tried several tips. The catsup was the best.

Bob Ruth
- Melbourne, Florida, USA

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