Some gaffer tape had been stuck to a plastic door for a long time. The
fabric rotted, leaving the adhesive. I wanted to remove this adhesive so
I tried
Label remover. Didn't work, and hardened the adhesive.
Gentle heat. Didn't help.
Wood chisel. Hopeless, and marked the door.
WD40. Softened a thin layer which came off as a smear on a cloth. It
would have taken 100 hours.
Meths. No effect. Considered drinking it.
Pressure washer. No effect.
Power sander. Removed a bit of it but clogged straight away and marked
the doorsome more.
Multitool with wallpaper removing tool. Worked fine.

Bill