not sure what caused this its from a mint set i just received. the spots that are silver/gray look like the were sanded maybe die abrasion.
It's just a scratch. Coins in Uncirculated sets were not as specially treated as coins made for proof sets. Uncirculated sets contained coins that were made for regular circulation. Scratches and all.
Check to see if what you are calling abrasions are on the plastic wrapper and not the coin. Of course, that is if the coins are still in the Mint packaging. Sometimes, scratches on the plastic outer wrapping looks like scratches on the coin.
there in the cello still its on the coin the coin its self is gold toned but the abrasions are silver