I got a bally blackjack when I first got into the hobby...someone had used incorrect clear coat (or perhaps it came from the factory)and it turned a yellowish color...so I stripped the playfield and fired up my palm sander...
things were going good for the first 5 minutes as I thought I could masterfully remove the ever-so-thin clear without touching the art underneath... then I used a cloth and some alcohol to wipe away the dust so I could admire my brilliance....UGH! I felt sick when I saw what I had done...live and learn