Bought this from a friend of mine who buys/sells coins, gold, etc. I like old copper from other countries as it can be had cheaper than most coins from the US at a relative age. 1st purchase was this 1806 British Penny. Got it for $10. After I got home, I noticed two interesting marks on the front and back. They look to be counter stamps to me, but wanted someone else's opinion. The other coin is a 1856 France Cinq Centimes. Does has some verdigris, but at $5 I thought it was a good purchase. I might soak it in olive oil for a week and see if that removes it.
I don't think they're counterstamps Detecto. Looks like a strike thru of some sort. I'm not an error expert, so let's wait for them to chime in. Nice coins though. Bruce
Don't use olive oil. If I were you, I'd get some Verdi-care. It'll work better without damaging your coin (Much like Acetone, only when used right).
The 1806 in this condition sells for around $3-$4. You can find them at shows in the junk boxes. The strike through won't add any thing to it. It's too worn a coin.: http://www.ebay.ca/sch/i.html?_nkw=1806&_sacat=3394&_odkw=&_osacat=3394&_trksid=p3286.c0.m270.l1313 The 5 centimes was a better buy. Usually $5-$10.
The 5c also has good looking surfaces for its age and will only go down with inappropriate cleaning. It is not a shiny penny and should not be expected to look like a 1956.
I'm inclined to go the other direction, but I would not call them counter stamps, more like graffiti. But graffiti that was stamped into the coin long after it was minted. IMO the images are too sharp and well defined for them to have been original with the coin. With that much wear they would show wear too and they do not.