look up Vid's guide to playfield restoration;
I'd guess...hit the area with a small rag with naptha on it (to clear wax and residue), hit it again with a small rag soaked in 90% isopropyl alcohol, use a couple fine paint pens or tooth picks with the matching paint colors to fill in the chips, then cover it with a fine layer of clear coat and/or a small square of mylar.
Good luck!