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I’ve tried all sorts, so come to this fount of all knowledge for the correct answer.
Old see through frame protection stickers. Hairdryer to get most of them off, but they leave some really sticky residue. I’ve tried degreaser, wd40, white spirit, meths and acetone to remove this mess. Acetone is the best (least worst?), but it seems to spread some of the goo around, which then promptly sticks again, so needs 4 or 5 attempts to get small bits off.
Any tips, or is it easier to get the frame shot blasted and repainted?
Car bug and tar remover ? You need paper towels too to absorb the crap and not move it about. Spray, let soak, wipe.
Autoglym intensive tar remover from Halfords/car accessory shop should do the job.
I used Screwfix sticky stuff remover to remove sticker residue off my van, excellent. You’ll have enough to do dozens of frames!

Naphtha (lighter fluid)
Its incredible useful and worth having a tin in the house.
Goo gone (goo and adhesive remover). We bought it from amazon and it has not yet failed whilst being gentle enough to get sticky crap off my rather lovely (expensive) norrona ski jacket.
Olive oil. Leave overnight if really stubborn. The best solution I found when removing ancient gorilla tape residue from rims.
Extra virgin, cold pressed?