This is an experiment we did when I was at school, so a couple of years ago now! Take a copper and leave it in coke overnight, the next day it comes out clean, if you leave it longer I remember the coin would actually start to dissolve!
Conclusions.
All that seemed to happen is the the ones that where in the coke over night look even dirtier than they did before!The 10 czk coin seems to be effect worse than the 20czk. This could be because it is copper platter and the 20 is brass platted.
Differences between now and my childhood experience:
- we use coca-cola when I was a child, not generic coke
- pre-1992 UK coins (1p and 2p) where 97% copper, rather than copper plated
Therefore: we should do this again with real coca-cola and see if we can find a pre-1992 English coin!