Have not tried PEI, I use Kapton Tape and TPU will pull it off. I print on a cold bed and I set my Z offset a little higher than it should be when using TPU so it does not lock on so tight. PETG you have to make sure the Z offset is correct, a little high and it balls up.. too low and you will never get it off.. For PETG you can try some glue stick and run under hot water to get the glue and the part off. Good luck