Cleaning Gold Coins - At Your Own Risk

[caloundracats]

Thank you for your detailed reply. Simply, the answer is no 😀

[sovereignsteve]

4 minutes ago, caloundracats said:

Thank you for your detailed reply. Simply, the answer is no 😀

Ha ha, sorry you can't take the scientist out of the numismatist!😂

[PansPurse]

For quick reference to anyone who skipped A-level chemistry, @sovereignsteve is referring to the length of polymer chain (the carbon atoms) attached to the alcohol (O-H) part of the molecule:

meth (methyl) = 1 carbon atom

eth (ethyl) = 2 carbon atoms

prop (propyl) = 3 carbon atoms

but (butyl) = 4 carbon atoms

pent (pentyl) = 5 carbon atoms

And the rest go predictably hex, sept, oct, non, dec and so forth.

[sovereignsteve]

and don't forget the isomers once you get to butanol and above, it has an appreciable effect on solvent action.

[caloundracats]

As a total non-chemist who didn't do A-level chemistry, a goldsmith once told me to wash gold jewellery in dishwashing liquid and warm water. But here we are talking coins. I know the jewellery came up trumps. No idea about gold coins though. There again, I don't intend to clean any of mine.

[sovereignsteve]

1 minute ago, caloundracats said:

wash gold jewellery in dishwashing liquid and warm water

yes should work but consider the type of dirt that jewellery will accumulate. Not likely to affect coins as much.

[Xander]

A Brillo pad would soon remove the dirt.😎

[5huggy]

1 hour ago, sovereignsteve said:

Ethanol and methanl, short chain alcohols, tend not to be much good as solvents. They have a restricted action on certain polar materials but you need to go past propanol to butanol and above to get any real action on organic materials.

WHOOOOOoooooo   the "Chemist" in you is ooozing out!  🤣

[danmc82]

6 hours ago, Xander said:

A Brillo pad would soon remove the dirt.😎

Would also tell you if the coin was gold plated or not 😁

[silenceissilver]

On 29/01/2019 at 14:25, KevinFlynn said:

For badly stained trade coins I am using a step method of soaking in a soapy solution (basic curd soap), then soaking in (boiling) hot distilled water, finally soaking in alcohol (isopropanol).

Leaving them to soak for a quarter of an hour each step or longer. No physical wiping or scratching. Just soaking and letting them dry. This works nicely.

Till recently I had only bullion, so didn't clean any proof coins. I put some of my Sovereigns into luke warm soap water for a few hours, then put them into just water for rinsing them, then I let them dry for a few hours on a towel. (Cotton gloves at every step) Didn't do any rubbing as many people warn it can leave micro scratches. Not that it would matter for bullion coins. Worked well. Not sure if I would do this with my newly acquired, secondary market, proof half Sovereigns but they seem to be fine. However after reading this thread, I might, if needed, in the future.

[Murph]

Only problem with going up to butanol, pentanol is the solubility drops down as well so you can’t mix them with a little water.  Unless you don’t use the straight chain isomers, I guess?

I’d think you probably have to pay more for them as well compared to ethanol or isopropanol.  I don’t think I would use meths anyway since the additives might leave marks if you didn’t rinse the coins well enough. 

I suppose you could use butane if you can’t get the alcohol?

[xthomasx]

On ‎01‎/‎02‎/‎2019 at 17:51, sovereignsteve said:

and don't forget the isomers once you get to butanol and above, it has an appreciable effect on solvent action.

 

You have isomers in propanol already.

[sovereignsteve]

1 hour ago, xthomasx said:

 

You have isomer in propanol already.

yes but only which carbon atom the hydroxyl group is on, propan-1-ol and propan-2-ol

I should have clarified that it's once you get on to branched chain isomers does it make a real difference.

[Auric1253]

Wouldn't dirt on sovereigns be of human origin? If bio laundry powder will eat human dirt off clothes, then why not off sovereigns?

No rubbing required just give good soak and rinse later.

PS what is the forum's view on the patina that older sovereigns have? Better left untouched, or removed with Cilit Bang to restore shiny appearance? The patina presumably comes from oxidation of the copper in 22 carat gold.

 

[sovereignsteve]

Just now, Auric1253 said:

PS what is the forum's view on the patina that older sovereigns have? Better left untouched, or removed with Cilit Bang to restore shiny appearance? The patina presumably comes from oxidation of the copper in 22 carat gold.

 

NCS do stuff like that, so obviously doesn't affect the coin in NGC's eyes.

[Oldun]

Cleaned a proof by fingers and a bit of fairy liquid, being careful not to actually touch the faces of the coin and then rinse and leave to dry, sent it to ngc with ncs thrown in on top to give it the best shot possible and got a PF70 Ultra Cameo. Not bad for a 2005 £2 proof sovereign bought at spot in a flip at an auction.

[sovereignsteve]

18 minutes ago, Oldun said:

Cleaned a proof by fingers and a bit of fairy liquid, being careful not to actually touch the faces of the coin and then rinse and leave to dry, sent it to ngc with ncs thrown in on top to give it the best shot possible and got a PF70 Ultra Cameo. Not bad for a 2005 £2 proof sovereign bought at spot in a flip at an auction.

Would have been interesting to see what it would have achieved if you'd just sent it for grading😉

[Oldun]

For sure. I did post a photo of it here somewhere. Will try to find it. Hang on.

[Oldun]

28 minutes ago, sovereignsteve said:

Would have been interesting to see what it would have achieved if you'd just sent it for grading😉

Here you go.

 

[danmc82]

3 hours ago, Oldun said:

Cleaned a proof by fingers and a bit of fairy liquid, being careful not to actually touch the faces of the coin and then rinse and leave to dry, sent it to ngc with ncs thrown in on top to give it the best shot possible and got a PF70 Ultra Cameo. Not bad for a 2005 £2 proof sovereign bought at spot in a flip at an auction.

How bad was it before? Similar to my halves?

[Seasider]

3 hours ago, Oldun said:

Cleaned a proof by fingers and a bit of fairy liquid, being careful not to actually touch the faces of the coin

I am a bit slow but how do you clean something with your fingers and not actually touch it?

[danmc82]

4 hours ago, Seasider said:

I am a bit slow but how do you clean something with your fingers and not actually touch it?

He meant he held the rim of the coin not the face.

[Oldun]

6 hours ago, Seasider said:

I am a bit slow but how do you clean something with your fingers and not actually touch it?

Washing up liquid is oily. I just very gently pushed the copious amount of oily liquid around the coin’s surface using the oil as a buffer, thereby never touching the surface. Zero pressure applied, and as mentioned above, held the coin by the rim.

[Oldun]

6 hours ago, danmc82 said:

How bad was it before? Similar to my halves?

The main reason I went for it was because I had bought it delivered for £490, so bullion price and had zero downside. Lucky for me, and with ncs to give it its best shot, it worked out very well for me.

[MancunianStacker]

Might experiment with the cutlery tray in my dishwasher and my household steam cleaner 😉