Quoted from vid1900:
Novus2 might be too harsh of an abrasive.
Many old Bally have flaky fragile paint.
Wipe carefully with Naphtha, and don't try to clean too much.
Was fairly successful cleaning this up by first dabbing with a soft cloth and naphtha, then rubbing lightly, making sure that the only flaking areas were around where the paint had already coming up, then cleaning the rest of it lightly with novus to remove the dirt the naphtha wouldn't get:
I also trimmed some of the dirty lifting mylar
I've run into problems where, no matter how carefully I cut, I'm still occasionally cutting into the wood with the exacto knife and leaving annoying white lines (much worse than the very occasional lifted paint). Is there anything I can do to make the cutting safer?
Finally, I ordered a sheet of mylar from the pinball resource, and just fit and attached my first piece (after waxing the area), only to realize that it's probably 3-4 times thinner than the existing mylar. Do you know of any place to buy thicker mylar? As it is, this isn't going to make it okay any better and stands out even more than if I don't put down any mylar all. I'm half tempted to just not do it, besides from putting new rings around the pop bumpers Am I at much danger of the mylar ripping up more from ball travel if I don't put more down? (if so I doubt the thinner mylar would help much either)