Using acetone to clean coins

[SilverAge3]

I've watched videos of people removing copper spots off gold with a torch. Seems to work, but not personally tried.

[Rob]

4 hours ago, SilverAge3 said:

I've watched videos of people removing copper spots off gold with a torch. Seems to work, but not personally tried.

Why on earth would people do this? The melting point of copper is 20 degrees higher than gold, so there's a real danger of melting the gold. The copper salts will also have a higher melting point. The best you can hope for is to alloy the copper and gold, which are chemically miscible.

[blakeyboy]

Since the gold used isn't pure, this is surely a eutectic situation, so you are even more correct?

[ozjohn]

On 3/20/2023 at 8:47 AM, Peckris 2 said:

don't forget surgical (or methylated) spirit.

I've found metho and a wood tooth pick useful for removing verdigris from the lettering around a  .500 Ag coin also a cotton bud for removing any remaining debris. I've heard there was some criticism about the dye residue from  mauve metho. I don't know about the UK but in Australia you can get metho with out any dye. Also useful as stated above for degreasing a coin.

Edited February 12, 2024 by ozjohn
more info

[jelida]

7 hours ago, ozjohn said:

I've found metho and a wood tooth pick useful for removing verdigris from the lettering around a  .500 Ag coin also a cotton bud for removing any remaining debris. I've heard there was some criticism about the dye residue from  mauve metho. I don't know about the UK but in Australia you can get metho with out any dye. Also useful as stated above for degreasing a coin.

The dye free meths over here is Industrial Methylated Spirit (IMS) and it is widely available.

Jerry

[Peckris 2]

13 hours ago, ozjohn said:

I've found metho and a wood tooth pick useful for removing verdigris from the lettering around a  .500 Ag coin also a cotton bud for removing any remaining debris. I've heard there was some criticism about the dye residue from  mauve metho. I don't know about the UK but in Australia you can get metho with out any dye. Also useful as stated above for degreasing a coin.

Presumably surgical spirit - being clear - doesn't have any dye problem?

[VickySilver]

We call it "rubbing alcohol" (not suitable for drinking!) over on this side of the Pond. A decent solvent and one of the choices. I have really come along to liking ammonia with no dyes, etc. for copper nickel or even silver in its alloys and even gold - not that implying this choice is encycopaedic but only amongst the possibilities..

[SilverAge3]

On 2/12/2024 at 2:28 PM, VickySilver said:

We call it "rubbing alcohol" (not suitable for drinking!) over on this side of the Pond. A decent solvent and one of the choices. I have really come along to liking ammonia with no dyes, etc. for copper nickel or even silver in its alloys and even gold - not that implying this choice is encycopaedic but only amongst the possibilities..

Anhydrous, or any grocery store ammonia? I'd think it better w/o water in it, esp w copper/bronze.

Edited February 22, 2024 by SilverAge3

[VickySilver]

Hmmm, I would def. avoid ammonia on copper or copper alloy.