Stop buying those PVC holders at flea markets - they ruin the patina on old coppers

I've seen four people this month alone with Roman bronzes that have that weird green crusty rot starting around the edges. Every single one was stored in those soft clear PVC flips from the 90s. That plastic outgasses something that eats copper alloy over time. I learned this the hard way with a Constantine I Follis I paid $30 for at a local park cleanup event. Three years in a PVC flip and the surface started flaking. Switched to Mylar and it stopped. Check your holders people. Especially if they smell like a new shower curtain.

2 comments

2 Comments

jade_lane1915d ago

Three years in a PVC flip and the surface started flaking" is exactly what I've been noticing too. But what about the older cardboard and plastic flips from like the 70s and 80s? I got a Trajan denarius in one of those last year and there's this weird yellowish residue on the back now. Did that old style plastic have the same outgassing problem or is it different from the 90s PVC ones?

kai_west15d ago

Did the 70s cardboard and plastic ones have that same soft PVC feel? If it's flexible and clear, it's probably PVC and causing the same damage. Old doesn't mean safe, just means it's had more time to offgas onto your coin.