My 1912-S Lincoln Wheat Penny

So here are the pics if anyone is interested;

First one is uncleaned original sitting in DI;

Second, after it had soaked for a while, then frozen;

Third, the stripped finish, working from the centre, outwards.

I note that the detruitus has taken on a waxy finsh. Longer in the H2O2 would have probably gone on to remove this entirely, however I was not concerned about cleaning it and so removed it.

Look at the post above. LOLOLOL

Quite right sir, I was a little shocked myself to see the first suggestion of soaking it in nail polish remover for a week!
The pictures of the farthing are a good illustration of what NOT to do, and the resulting destruction of the patina, although I note the pictorial evidence was still questioned by someone.
I really am most grateful for folks' suggestions, certainly professionals with experience. I love my H2O2 for other cleaning uses, and I wanted to try for myself on an old coin

Somebody said lighter fluid was really good for taking off gunk. I dont remember the member.

If it's not water or acetone, things get ruined. You shouldn't clean something unless its the way YOU want the coin. I for one cleaned some REALLY rusty 43 steel cents, because I wanted a steel cent not a rusted chip of metal! (I thought they were copper cents until I used a magnet on them, THAT was a lot of rust)
I figured they weren't valuable, and to me they were ugly.

So its your coin. if you like how it turned out, good! It's your piece. Just know that if you touch a coin with harsh solvent (anything past water/acetone)
It a james bond coin:

For Your Eyes Only



</opinion based post>

My (not at all scientific or proven) reason for freezin' was to see if the expansion, then thaw cycle provoked enough movement on a molecular level to remove some of the crud. My theory was that when the DI froze around the coin and subsequently expanded, this was maybe enough to remove some, in the most gentle fashion. Since the crud appears to be petroleum based (grease), rather than organic, this wasn't particularly efficacious.

As I mentioned in another post, I'm popping over to a metalurgist friend next week to have a borrow of his XRF gun. This man could talk the birds out of the trees when it comes to chemistry/metalurgy, so I shall be speaking to him regarding the finer points of the oxygen/copper/ionic reactions which are taking place, and more importantly, what sort of chemical reaction I want to precipitate in order to achieve the desred result (crud removed; patina/colouration retained)

In response to something mentioned earlier, I'll make sure I photograph and time the experiment.

I know it is probably tantamount to blasphemy to a numismatist, but I am sure, with my rudimentary knowledge, that the coin could probably be stripped clean to bare copper, then have the patina/colour restored with some sort of CVD process. A wee bit far for a £20 coin, but interesting nonetheless. My experience in semiconductor engineering suggests to me that there is little that cannot be manipulated on an ionic/atomic level, assuming the appropriate gasses, temperatures and pressures.

I also must make clear that I am in no way attempting this to rip some poor bugger off with a "1st class specimen". I'll be keeping the coin whatever happens, so my motive is not to deceive! I just don't want gunky coins!

I am aware that peroxide is an oxidating agent. I know the effects an oxidating agent has on metals. I was asking Thad to explain it as the only comment was don't use it it is horrible. I thought a clarification would be a good thing.

Next time I will just keep my fingers shut. Sheesh.