PVC Residue On Coins

That's sound advice.

As a couple of very general "rules of thumb":
- PVC residue is green. Copper is the element usually involved in PVC reaction, and most copper corrosion byproducts are green-coloured. So if a coin is copper, bronze, brass or diluted silver, and has bits of green on it, and is less than 500 years old, then it's possible that it's PVC damage. It could of course be ordinary environmental corrosion, so see the other tests below. Metals that do not react strongly with acids (such as gold, high-purity silver and pure nickel) are less prone to being affected by PVC.
- PVC residue is sticky. If the green stuff, or the coin generally, "feels sticky" and not like a normal coin from change, then PVC is a likely reason.
- PVC-affected coins "smell plasticky".
- If a coin has been sitting in a PVC coin album page for a long time, then a "shadow" of the coin is often visible in the album page after the coin is removed.
- Finally, PVC residue washes off in acetone, or other organic solvents. If the green goo comes off in acetone, then it was PVC.

"PVC damage" is caused when acidic plasticizers in the PVC slowly leach out of the plastic, and onto the coin. The acid reacts with the surface of the coin at the point of contact with the plastic. For coins that have not had too much exposure to the PVC, the damage is minimal. But for badly affected coins, the damage is irreversible. Acetone can remove the PVC goo and prevent further damage from happening, but the damage already done cannot be undone. This might be seen as discolouration, and in the "hazing" or dulling of reflective surfaces on high-grade coins.

I don't see any signs of PVC damage, just typical toning. And PVC is much less likely to affect a silver coin than a copper one. I certainly wouldn't break a graded coin out of its holder just to check.

@Zurie: the coin has a nice toning but it also has some kind of dirt or residue around the lettering... its visible for example on WIL of Wilhelm. Could that be PVC residue or just harmless dirt?

All green is not PVC damage. Looks like normal toning to me.

True, most is probably from copper reacting to salts and skin oils

There are plenty of more recent threads - it's a topic that come sup quite frequently around here - but this one will do.

I generally don't rinse any coin unless it's got visible PVC goo and/or it is "sticky" to the touch. But that's just because I'm cheap and acetone isn't cheap, so I restrict its use to coins that I know will need it.

For PVC goo, acetone works fast - soaking longer than 5 minutes is redundant. If it doesn't come off in 5 minutes, it's not PVC goo.

Rinsing with distilled water is also unnecessary. If you've acetone-rinsed properly, there shouldn't be anything on the coin for distilled water to remove, and if you haven't rinsed with acetone properly, then whatever's still on the coin isn't going to come off in water. Water can also be harmful to copper coins if it's not dried off properly - and acetone is an excellent drying agent. Personally, I'd do it the other way around - give the coins a water rinse first to remove anything water-soluble, then acetone.

A distilled water rinse is essential for E-Z-est or other acidic dips, because you need to wash the acid off or it'll eat into your coin. This is not a concern with acetone as it's not acidic.