Would a variation of the backglass saran wrap trick work on this playfield?

https://pinside.com/pinball/forum/topic/backglass-advice-krylon-triple-thick

This might work to flatten the flaking. Then you would have to add multiple layers of crystal clear for good coverage. Of course, you would have to use something besides Krylon Triple Thick. I've used Krylon #1303 Crystal Clear Acrylic with good results. I have had problems with fish eyes but I think that is because I didn't use thin coats that were allowed to dry for 24 hours before applying the next coat. It sands well after drying.

I buy it at Michael's for about $9.00 less the 40-50% coupon discount, or about $5.00. You will need about two cans for a 'flat' playfield, probably more for your playfield.

Amazon has six cans for $39.99:

https://www.amazon.com/Krylon-Crystal-Acrylic-Coating-Artist/dp/B0042T3SDG/ref=sr_1_1/144-0076069-7929717

I hate to see artwork this old destroyed. I sure hope that you can find a way to save that playfield @zacaj.

Yeah, never tried it myself.

I just got a Four Million B.C. and had to check the playfield, again, after reading your post. Fortunately, I don't have any of these issues.

We have the opposite problem here in Tucson. I bought a Royal Flush years ago that had terrible playfield ink bubbling. I think that was caused by storing it in a hot storage unit for years - very hot summers followed by cold winters. Sadly, that playfield is beyond repair, but maybe @zacaj's can be saved.