I'd slap some paint on there and drop them on some bees. I'd probably keep them on 2 or three hives just to see if there's an adverse reaction of any form. They will clean them up into a useable condition if they don't like what they see.
Scorching the insides of the super body it would kill any possible diseases. However, this leaves the frames alone to pass on those very diseases too. You can't easily treat frames though. If you're going to scorch the super bodies to avoid disease you're best to throwing away the frames and start with new frames as well.I would scorch the insides with a propane torch and then use them. Don't take chances with AFB.