Cleaning?

[Dirt Monkey 1 3]

I have bought some coins from eBay and a couple have arrived with dark stick patches on them ? looks like they may have had sticky labels on them at some point. While I am a beginner, I have read enough on here to know that dipping them and scrubbing them with a Brillo pad is a bad thing. Can anyone suggest a gentle cleaning method that will take this goo off without damaging the coin. I thought about alcohol and a cotton bud but don't know if it will damage the lustre.

Cheers in advance.

Jason

[DaveG38 405]

I'm not guaranteeing it won't affect the coins surface, but people on here have, in the past, recommended using acetone for gentle cleaning. The overall experience has been one of not affecting the toning of the coin being cleaned. The advantage of using this substance is that it will shift most gummy residues e.g from cellotape, labels etc. The only downside may be that once you have used it and cleaned off the face of the coin, incluidng the goo, you find that the sticky patches have themselves affected the overall toning of the coin, so that you are left with patches, except they won't be sticky any more.

[Peckris 579]

Are they silver, or copper / bronze? Silver can be gently washed (I'd use pure soap flakes myself) and rinsed then dabbed dry with a towel. Copper and bronze, you could try acetone (NOT nail polish remover!!), or I've used surgical spirit - which is alcohol - with a microfibre cloth rather than a cotton bud.

[Dirt Monkey 1 3]

Thanks for the advice again, just need to find some acetone now.

[DaveG38 405]

As Peckris says DON'T use simple nail polish remover - try the chemists for pure acetone.

[Coinery 1,153]

Yes, nail varnish remover contains moisturisers! Some supermarkets (with instore chemists), and Lloyds Chemist stock it!

Edit to add: as Dave similarly mentioned, the sticky stuff may have been on the coin BEFORE the tone the coin has now, which means you may end up with light 'untoned' spots, instead of sticky ones?

Edited August 16, 2014 by Coinery

[Peter 615]

I've used Goddards silver dip with a cotton bud on some silver coins,

Experiment

[Danelaw 208]

I've used Goddards silver dip with a cotton bud on some silver coins,

Experiment

[Peckris 579]

I've used Goddards silver dip with a cotton bud on some silver coins,

Experiment

Goddards is perfectly ok IF you follow some basic rules :

1. Never fully immerse for longer than 10 seconds, rinse thoroughly and dab dry.

2. If using on a cotton bud, don't let the dip be in contact with the stain for any longer than necessary, and wash off as in 1. If it still won't come off, abandon using dip.

3. Never use dip on a proof.

4. Never use dip on a coin with attractive natural toning.

[Dirt Monkey 1 3]

Again great advice, thank you all. Got some acetone and it worked a treat, thank you. Think I will leave the Goddards until I'm a bit more experienced.

[PWA 1967 2,135]

Parcel posted today jason .Happy collecting

[Peter 615]

Goodards,a soft tooth pick and careful work will do the job.I never dip.

Apart from the skinny type after a few Abbot Ales.

Although at my age I prefer shorts that cover my nipples.

[sound 25]

Thanks for the advice again, just need to find some acetone now.

Asda sell it for £1.00 a small bottle in their pharmacy section. Ask at the counter.

Mark

[ozjohn 647]

Dunno about Godards dip as most silver dips contain sulfuric acid. Try a couple of teaspoons bicarb of soda dissolved in boiling water with aluminum foil in the bottom of the dish. Put coin in solution on to the foil for a few seconds remove then wash and examine. Repeat as necessary. I think this method of chemical cleaning is less aggressive than acid based dips as it converts the silver sulfide back into silver metal and does not remove anything from the coin. Probably a good idea to degrease the coin with metho beforehand. Caution all cleaning of coins should be done as a last resort and not embarked upon lightly. Also much cheaper than dips even if the hot water is hard on the fingers.

[Peckris 579]

Dunno about Godards dip as most silver dips contain sulfuric acid. Try a couple of teaspoons bicarb of soda dissolved in boiling water with aluminum foil in the bottom of the dish. Put coin in solution on to the foil for a few seconds remove then wash and examine. Repeat as necessary. I think this method of chemical cleaning is less aggressive than acid based dips as it converts the silver sulfide back into silver metal and does not remove anything from the coin. Probably a good idea to degrease the coin with metho beforehand. Caution all cleaning of coins should be done as a last resort and not embarked upon lightly. Also much cheaper than dips even if the hot water is hard on the fingers.

Goddards contains uric acid, same as if you'd dunked the coin into.. into.. well, you get the picture (I'm not taking the p*ss, honest).

[ozjohn 647]

Its still an acid (which is less corrosive than Sulfuric acid) that removes the oxides and sulfides which means some of the coin is removed during the cleaning process whereas the method above converts the sulfides back into the original metal. Perhaps a chemist amongst us could comment as my chemistry is limited to a one semester undergraduate course.

[Peckris 579]

Its still an acid (which is less corrosive than Sulfuric acid) that removes the oxides and sulfides which means some of the coin is removed during the cleaning process whereas the method above converts the sulfides back into the original metal. Perhaps a chemist amongst us could comment as my chemistry is limited to a one semester undergraduate course.

Speaking from practical experience (I'm not a chemist) - BRIEF dipping in Goddards (10 seconds followed by a further 10 seconds maximum after rinsing and inspection) can work as intended, but if this treatment does not work, the 'problem - whatever it is - should be tackled another way. I would only ever use Goddards in this way for a badly and ugly tarnished silver coin. It MUST be rinsed thoroughly afterwards, to removed all traces of the mild acid. Done this way, only surface impurities are removed.

[Coinery 1,153]

I understand your anxiety, OJ, I've been there myself! Get a bag of old coins and have a play with these things, resolve it for yourself...no amount of words will convince you otherwise, you know that!

[Peter 615]

I've treated a few 1937 crowns which have isolated staining.

Never a full dip.