I have an old 1991 Les Paul Classic that has aged really nicely. LOTS of checking, few finish cracks here and there. There is a pretty severe finish crack along-between the top volume/tone knobs and another between the bottom volume/tone knobs. Probably from sweat years ago and being put away wet LOL. I'd done some refurbishment on the bits (Duncan Seth Lover pups, new pots/caps, jack) a year or so ago and while apart I got up close and personal with those two cracks as they appeared to be starting to curl up where the split/cracks appear. Played it for a couple weeks and put it back up until the other day. Lo and behold the nitro had flattened back down apparently. I'm going to leave well enough alone at this point as the checking is really nice as it is. Because it's a full Bullion Gold (front/back/neck) guitar from the factory I really don't want to strip it all off. My question to anyone with more experience than me is- Is it practical to spray clear over a vintage finish? Of course it would have to be cleaned off and lightly sanded first. I've sprayed plenty of lacquer on new builds but never attempted anything like this with an older, vintage guitar. OTOH I'm pretty sure after all the years of sweat, smoke and beer soaking in, just cleaning it up to spray might cause more damage than exists. I'm thinking that it may have been heat and moisture affecting the nitro as the curling was during summer in Florida, hot and humid. Currently it's looking good and not curling, it's been cooler and very low humidity the last couple of months. Any ideas, suggestions? Sometimes it's better to leave well enough alone, ha ha ha, been there, done that bought the Tee shirt as a reminder. Thanks in advance.