I would try a product called replacetone, a noncaustic alternative to
acetone. It might be more difficult to find and possible more
expensive, but it won't kill your hands or sensitive parts of your
machine. Another thing to try would be turpenoid, sorta like
turpentine, but not solvent based. Worked well on some paint brushes
soaked in tar. The best product would probably be the resin remover
sold for saw blades. This is probably what they were refering to in
the instructions. This stuff is so useful, though,I would definitly
buy a can of it. It works wonders on everything that cuts, even bench
plane soles and irons.