I've never had paint come up with the mylar using the spray/freeze method....
First step (the easy step) is the freeze the mylar with a airduster can and pull it off. Takes about 2 minutes.
Then I pour high % isop alcohol over the PF (the highest I can find here is 91%).
Sprinkle a liberal amount of flour over the PF, work it into the alcohol with fingers.
Let it sit for 5 mins.
Use a putty knife (plastic) to get the first layer of adhesive up.
Vaccuum PF to remove excess flour.
Repeat alcohol and flour step again.
Use rag to get up the rest of the adhesive.
Best method i've used. Doesnt compromise the PF, no nasty chemicals or greasy gross orange cleaner. I've probably done it 5-10 times with great results each time.