Copper Marevidi, double stamped?

[Tuberale]

Similar in size and overall shape to a cob identified as a copper 8 Maravedi. This cob appears to have a lion within a shield on both sides. In addition, both sides appear to have had another impression counter-stamped on the shields, harder so that it is actually lower than the now raised shield.

Appears to be copper based on sound of coin on my table.

May be a date lower left on photo copper2a, but can't make it out.

[stevemc]

Definitly double-stamped. Nice! I was wondering about your cleaning with acetone. This is not the normal cleaning solution. No pun intended. Usually it is muratic acid. I didnt know acetone would take off copper or silver tarnish. Usually acetone is for finger nail polish remover that type of thing. Did you figure out what the coins are yet? Metal wise?

[Tuberale]

The first coin was identified as an 8 Maravedi, which would be copper. Assuming this is the same.

Acetone is about the gentleist thing for cleaning. It reacts only with organic material: soil, oil, grime, skin flakes, etc. Has no effect on patina at all. I'm guessing (just guessing) the patina for 300 year old coins may be important to keep, so not much interested in acid treatments, which also remove metal.

[stevemc]

Actually muratic acid wont do anything to copper or silver. But it will clean off anything else, and bring them down to a just made color, which might not be wanted. But you might want to keep the patina, which you partially removed by cleaning. I am very surprised that acetone removed any tarnish/patina. I feel that leaving them alone , often will make them more valuable, unless you cant make out any details.

[divewrecks]

Here is a whole thread on cleaning coins with Acetone.....

http://www.coinpeople.com/index.php?...your-thoughts/

Stan

[Tuberale]

Here is a whole thread on cleaning coins with Acetone.....

http://www.coinpeople.com/index.php?...your-thoughts/

Stan

And after reading the entire thread, I noticed no one said a word after a chemistry teacher debunked copper reacting to acetone. The original article cited left several important data out of their equation, to wit, presence of water.

Until I hear otherwise from a competent scientist, will continue to use acetone on circulated coins or soiled coins of probable circulation.