I had an idea before on mylar removal, the only thing is I have not tested it so cant vouch for its effectiveness.

How a bout leaving the whole playfield in the sun for maybe 15 minutes.
this should heat up the mylar and glue underneath and make it a bit easier to remove.

I wouldn't leave it too long in case it warps.

if that works then all you need to do is remove any glue residue.

Has anyone else tried something similar?

In theory - it should work. ESPECIALLY on older games with "contact" - Not mylar

I choose to do sections so that I am forced to work at a slow pace. I'm an impatient bastard, so I'd probably try to do the entire playfield at once and create myself a disaster !