I reuse enclosures for my own stuff. I don't use decals though, so it's usually a matter of sanding down/stripping the paint/labels and re-spraying. I sometimes end up using JB Weld to fill extra holes too.
You're right, it might do the trick. I put 3 transparent coating on the waterslide sheets before I put them on enclosures. It may be super easy. I will do some testing with scraps I got.