If you just found a coin with green crust on it and you’re wondering if it’s dangerous, you’re not alone. That green stuff is called verdigris, and it shows up on a lot of older pennies and copper coins. The short answer: it’s not deadly, but you shouldn’t eat it. Verdigris can be mildly toxic…
Acetone gets thrown around a lot in coin forums. Sometimes as a miracle fix, sometimes as a dangerous tool for people who don’t know what they’re doing. The truth is somewhere in the middle. Acetone is a solvent that can safely remove certain types of surface contaminants without damaging the metal underneath, if it’s used…
Tarnish is the thin layer of surface discoloration that forms on a coin when it reacts with elements in the environment like oxygen, sulfur, or moisture. It’s not deep corrosion, and it doesn’t usually eat into the metal. Instead, tarnish sits on the surface and changes the coin’s color. Sometimes slightly, sometimes dramatically. It’s most…
In the world of coin collecting, the line between “tarnish” and “toning” is surprisingly thin, and often debated. Both are surface changes caused by chemical reactions, usually with sulfur or oxygen, but one is often seen as damage while the other might add hundreds (or thousands) of dollars in value. So what’s the real difference?…
Not all discoloration on a coin is bad, but it’s not all good either. Tarnish is one of the most common surface changes collectors encounter, especially on silver coins. It’s the dull film that creeps across a coin’s surface over time, shifting its luster and tone without necessarily damaging the metal itself. This post is…
Verdigris isn’t just a problem for the coin it appears on — it’s contagious. If you’ve got a coin with active green corrosion sitting in a flip, tube, or roll, it could be slowly eating away at everything it touches. In our last post, we broke down what verdigris is and how to spot it….
Verdigris is that weird green stuff you sometimes see on old copper or bronze coins. It can range from a faint, minty haze to thick, crusty blobs that look like the coin was stored in a compost pile. And while it might look kind of cool in certain lighting, it’s not a sign of anything…
If you’ve ever submitted a coin for grading and gotten the dreaded Environmental Damage tag back from PCGS, you know how frustrating it can be. Unlike more specific designations like “Cleaned” or “Scratched,” this one feels like a catch-all, but there’s a little more to it than that. This post breaks down exactly what PCGS…
You’ll see both of these terms tossed around a lot in coin collecting, especially when it comes to details grades, and sometimes they’re used interchangeably. But while they overlap, they’re not identical. Think of it like this: all corrosion is environmental damage, but not all environmental damage is corrosion. In this post, we’ll clear up…
The phrase “shipwreck coin” carries a certain mystique. It conjures images of buried treasure, sunken galleons, and ocean-crusted riches pulled from the deep. But what does that actually mean for a coin’s condition? This post strips away the romance and looks at the science. We’ll break down what shipwreck corrosion really is, how it affects…