Damage/erosion on Greek Circulated 2-euro coins

Hello, 

I started noticing these type of damage on a few 2-euro coins, which were more or less AU. 

I am storing them in a clear PVC, multiple-grid case.

Any way this is due to poor storage, i.e. should I change the case?

Thank you in advance.

Konstantinos

Doesnt PVC ruin coins if so that’s probably the reason

Update: these coins were swapped with a colleague of mine. They were given to me into a plastic pouch. It was probably PVC and reacted with the coins.. 

SenhorDinheiro

Doesnt PVC ruin coins if so that’s probably the reason

+1

Yeah just look for pvc free when buying something to store them