White film developing on black plastic glasses?

[chasingred]

Not sure if this is best posted here, so please let me know if I should move this thread.

I have a pair of Shuron Ronsir glasses. They're browlines with black plastic for most of the frame. About three months ago, I've noticed that a white film has been developing on the plastic, almost as though the plastic was being stripped of some finish and the part underneath was "drying out" or something. Any idea what's going on and how I can repair this?

 

[Aldehyde]

I've had this happen to acetate frames and buffed it off using black rouge on a bench grinder / buffer. Then used renaissance wax to protect and have not had it reoccur.

 

[C-Note]

I'm not sure but I know things limescale can build up on plastic, not saying that's necessarily the case but it might be. In which case I've read vinegar can take care of it but usually limescale builds when the plastic is left wet so if the glasses didn't get wet then Aldehyde's suggestion is probably better.