Why did this happen?

I soaked a pair of hand fabricated sterling silver end caps in
acetone over night to remove the epoxy from inside them. The silver
immediately began to turn colors - blue and black. It reminds me of
the discoloration on my chrome Harley pipes. A piece of unheated
sterling in the same bath didn’t change colors. It didn’t easily
polish off, so I resorted to fine grit sanding to remove.

I’ve soaked commercially made end caps in acetone before, with no
ill effects. So I’m wondering whether this issue is the result of
something that occurred as a result of my fabrication of the pieces?
Or might it have anything to with the types of glue/epoxies used
(super glue and Devcon 5 minute epoxy)? Or might it have to do with
the tiny rare earth magnets I’d glued inside the end caps, in an
attempt to devise a magnetic closure?

Any thoughts on this would be helpful.

Linda in central FL
Who’s wondering whether a gremlin has invaded my workspace…

Linda,

I don’t know but a guess suggests the commercially made product was
plated with something and your hand made product wasn’t. And I
imagine the stain will buff off.

Don Meixner