Melted my pant leg onto the pipes a week or so ago. The wife was thrilled
The melted plastic blob stayed on the pipe for a few days and then magically popped off in a single piece. Maybe the temperature changed and the CTEs were sufficiently different to break the adhesion. You might try dry ice if the adhered material is plastic-like...
BTW, I also have a car cover with holes in it from the pipes. Sh!t happens...