Tried this tonight on the funhouse I just removed the Mylar as well tonight. I haven't really tried other methods to remove the glue except for on a T2 with diamond plating and it wasn't real easy with a rag and Shellie.
This method seemed quicker and less labour intensive. Basically a put flour on let it sit for a moment and then rubbed it in until it became a little sandy, a quick drizzle of white spirits and rub it lightly in, followed by a sprinkle of flour and the rub until doughy glue comes off. Sprinkle a bit more to get any left over residue.
The great thing about the flour is that it highlights the glue, even the small bits you normally miss. I give it a thumbs up but interested to hear from others that have done playfield restores involving Mylar removal.
By the way, I had no paint loss except around the scoop, pop bumpers and step ramp drop zone where previous touch ups were made. I was amazed with the result and will document how I did this if interested. I forgot, I lost about 1.5mm of the corner of the 250k insert decal. Was spewing but happy that this was the worst thing that happened when removing factory mylar