This only applies to ABR-1 bridges, but I have done it to all my Historic LPs and it works wonders. Most players think the nut is the root of Gibson tuning issues, but in my experience it is usually the bridge. It sits loose on the studs and slides around, causing all sorts of tuning instability. The fix is to grab a hammer and gently tap each stud outward, away from the guitar's center line. With just enough hammering, the bridge will lock firmly against the studs. The bridge will not move around anymore and the guitar will stay in tune much longer.