As for your playfield, strip the entire playfield, clean it well with baby bum wipes, give it a polish n be careful.
Over n above that, use new balls n seek advice from a professional like Tim at Hot Rodded Pins who does playfield restores. I mention him cause he has a proven track record with a spray booth n clearcoating so far and is fully set up n ready for your work so to speak. There are others out there, but get quotes.
I did have a look for Tim's Phone number but couldn't find one ?