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