chris421649

Proofs should never be washed, even if toned. However, early Mint proofs are notorious for toning, from 1970 to 1982, and the early years are the worst. The alloy was quite normal - cupro-nickel didn't change, even with decimalisation. It was probably more to do with either the foam inserts in the plastic sets, or the glue they used. I'm afraid you will have to live with the toning, but if you want to upgrade your coin, 1970 proof shillings are only a couple of pounds. I have a 1970 Proof set in the plastic case they were issued in and they have no marks at all, this is what made me think it was the alloy. It looks more like a Grey fungus than toning.

Proofs should never be washed, even if toned. However, early Mint proofs are notorious for toning, from 1970 to 1982, and the early years are the worst. The alloy was quite normal - cupro-nickel didn't change, even with decimalisation. It was probably more to do with either the foam inserts in the plastic sets, or the glue they used. I'm afraid you will have to live with the toning, but if you want to upgrade your coin, 1970 proof shillings are only a couple of pounds.

I have just looked at a 1970 proof shilling I have. It has developed grey marks which cannot be removed with soap and water. The 1967 coin next to it and none of the other coins on the tray seem to be affected. My question is did the Royal Mint use a different alloy in the 1970 issue. Maybe the same alloy they used in the decimal coins. The coins are kept in a wooden cabinet on wooden trays with a felt disc underneath. The marks are on the side which was in contact with the felt. Any ideas.