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Rock Tumbling Coins

PostPosted: Wed May 20, 2020 9:44 pm
by Dr. Cadmium
I have been saving coins that are corroded and/or very dirty. These are ones that are not collectible, and would not clean up easily with acetone. I'm trying to get them suitable to return them to circulation.

Does anyone have any recipes for running junk clad through a rock tumbler? Length of time and preferred additives?. I've come across several guides and YouTube videos full of conflicting and unsatisfactory information. I figured I would ask here where there are people who deal in bulk.

Re: Rock Tumbling Coins

PostPosted: Wed May 20, 2020 10:12 pm
by coppernickel
If they will go through a coin counter, that is good enough. The ugliest go to coinstar. If they are sticky they may get a wash in dish soap.

Re: Rock Tumbling Coins

PostPosted: Wed May 20, 2020 11:09 pm
by galenrog
Any mild liquid soap will do. Dish soap, as coppernickel mentioned, is fine. As to how much time, rinse thoroughly after about 30 minutes. If some clad still gunky, go for another 30 minutes. This also works for copper cents. Zinc cents, if rot has already started, this method may accelerate the problem.

Time for more coffee.

Re: Rock Tumbling Coins

PostPosted: Fri May 22, 2020 11:28 am
by fasteddy
I have used a brass vibrating unit like what you would use for cleaning brass cartridge cases with mixed results...I have also used a ultra sonic bath with good results...

Re: Rock Tumbling Coins

PostPosted: Fri May 22, 2020 2:55 pm
by wolvesdad
fasteddy wrote:..I have also used a ultra sonic bath with good results...


A friend has one of these that i had talked about borrowing.

What media/solution did you use?
How full did you fill the bath? Coins on coins or a single layer? 3 or 5 or 10 layers thick? Roughly?

Thanks!!

Re: Rock Tumbling Coins

PostPosted: Fri May 22, 2020 3:26 pm
by AGgressive Metal
Portland Mint used a propane heater and cement mixer, along with some industrial solvent, to clean up coins that were recovered from a natural disaster. :D

Re: Rock Tumbling Coins

PostPosted: Wed May 27, 2020 9:17 am
by fasteddy
wolvesdad wrote:
fasteddy wrote:..I have also used a ultra sonic bath with good results...


A friend has one of these that i had talked about borrowing.

What media/solution did you use?
How full did you fill the bath? Coins on coins or a single layer? 3 or 5 or 10 layers thick? Roughly?

Thanks!!


I have a Hornady sonic cleaner...I used the Hornady solution with DI water per the instructions, I didn't have a lot of coin...maybe 3 dozen...they came from a vehicle drink cup holder and they were pretty nasty...gunked up with dried soda and cigarette ash...The bath can be set for intervals of 90 seconds, after each 90 seconds I stirred the coin in the basket. I did this maybe 5 or 6 times. The coin came clean enough to spend.

I have tried it on silver quarters...with not impressive results...the tarnish was still there, the flat areas were still flat but the smoothed/polished areas were pretty shiny after running through the sonic bath.

If you got some really nasty coin give it a shot....Good Luck.

Re: Rock Tumbling Coins

PostPosted: Sun May 31, 2020 8:41 am
by henrysmedford

Re: Rock Tumbling Coins

PostPosted: Tue Jun 02, 2020 10:56 am
by Dr. Cadmium
Thank you for the advice, everyone. Dish soap and 30-60 minutes depending on condition worked well. I have a couple of ikes that are still too dirty with paint and some kind of cement on them that I may try boling.