A recent example from our conservation laboratory.
It may be trendy to be “green” today, but for a coin, being green is not a good thing. Green can be the sign of PVC residues and corrosion; both of which are not what you want to see on the surface of your coin. Getting the green off is why this 1928 Peace Dollar was submitted to NCS.
Residues caused by the plasticizer PVC from inexpensive soft flips will cause a coin to develop green haze. Further development will cause this haze to turn into thick green deposits and then even further development will cause damage to the surface of a coin. Removal of this residue in its earliest stages is important. Several large deposits of green PVC residue can be seen on the reverse at the eagle’s tail and behind the eagle’s head. Removing this PVC residue from this otherwise nearly white silver coin will both allow the coin to be certified with NGC and keep the surfaces safe and beautiful for the long term. After careful conservation of this coin, it was able to grade numerically with NGC.