What is the difference between PVC and Verdigris?

WildWestHalfDollars

What causes Verdigris? And how do you clean a coin with that vs PVC?

WildWestHalfDollars

I am no scientist hence my question.

jmlanzaf

Verdigris is oxidation/corrosion of the surface of the coin.

PVC is a plastic that when it decomposes causes acid etching of the surface. Technically, the issue isn't PVC, it's damage caused by a decay product of PVC. You can rinse off the decayed PVC residue but if it has etched the surface, the etching stays.

The verdigris IS the surface of the coin. It cannot be removed without leaving evidence of its presence as you are removing the surface. If it is just beginning, you will end up with a slightly etched surface. If it had progressed, you would end up with a heavily pitted surface. It is irreversible.

WildWestHalfDollars

@jmlanzaf said:
Verdigris is oxidation/corrosion of the surface of the coin.

PVC is a plastic that when it decomposes causes acid etching of the surface. Technically, the issue isn't PVC, it's damage caused by a decay product of PVC. You can rinse off the decayed PVC residue but if it has etched the surface, the etching stays.

The verdigris IS the surface of the coin. It cannot be removed without leaving evidence of its presence as you are removing the surface. If it is just beginning, you will end up with a slightly etched surface. If it had progressed, you would end up with a heavily pitted surface. It is irreversible.

But don't many coins have toning is that what you mean? I mean early verdigris.

jmlanzaf

@PillarDollarCollector said:

@jmlanzaf said:
Verdigris is oxidation/corrosion of the surface of the coin.

PVC is a plastic that when it decomposes causes acid etching of the surface. Technically, the issue isn't PVC, it's damage caused by a decay product of PVC. You can rinse off the decayed PVC residue but if it has etched the surface, the etching stays.

The verdigris IS the surface of the coin. It cannot be removed without leaving evidence of its presence as you are removing the surface. If it is just beginning, you will end up with a slightly etched surface. If it had progressed, you would end up with a heavily pitted surface. It is irreversible.

But don't many coins have toning is that what you mean? I mean early verdigris.

Verdigris is not toning. I mean they are both chemical reactions of the surface but verdigris goes deeper and is usually, I believe, an acetate or hydroxide. Most light toning is usually a sulfide.

Edited to correct the chemical composition.

jmlanzaf

@PillarDollarCollector said:

@jmlanzaf said:
Verdigris is oxidation/corrosion of the surface of the coin.

PVC is a plastic that when it decomposes causes acid etching of the surface. Technically, the issue isn't PVC, it's damage caused by a decay product of PVC. You can rinse off the decayed PVC residue but if it has etched the surface, the etching stays.

The verdigris IS the surface of the coin. It cannot be removed without leaving evidence of its presence as you are removing the surface. If it is just beginning, you will end up with a slightly etched surface. If it had progressed, you would end up with a heavily pitted surface. It is irreversible.

But don't many coins have toning is that what you mean? I mean early verdigris.

This is verdigris

jmlanzaf

The chemical progression is different. "Toning" ends in a terminal black layer. Verdigris ends up in an often lumpy blue/ green

jmlanzaf

Most sources identify the verdigris as copper acetate or copper hydroxide.

WildWestHalfDollars

Does verdigris affect silver and gold coins? And what causes it?

may

@PillarDollarCollector said:
Does verdigris affect silver and gold coins? And what causes it?

Sometimes it can, though not as much as copper. It can be caused by the environment or chemicals.