Not too sure on home remedies but Grunge-Off, Goo-off, Goo-B-GOne (ok i made that up) and even fingernail polish remover work for removing adhesive film. I would be too worried to use the fingernail polish remover - it has acetone and other . . . . icky stuff. Not to keen on the WD40 solution either.

I say sandblast that sucker.