I'll ask him

When I tried with a blade it rolled across the room, or I'd be afraid I'd puncture the plastic coating. It's a tiny magnet.

If acetone will discolor the plastic, I don't care about that. If the acetone does damage though, like erosion, I don't want to risk it.

It's this magnet:
https://www.kjmagnetics.com/proddeta...prod=D84PC-BLK

1/2" diameter, 1/4" thick. It costs 95 cents... so I'm not heartbroken if it doesn't work out. But hey, a buck is a buck. Waste not, want not.