I've heard that nail polish remover is good. Also heard steaming the chassis is good as well. Never tried either though. I'm not sure if nail polish remover is a good idea because it might break down the enamel coating on the wire.......
I'ld try the steaming before the nail polish remover, I don't think it would work though. Like ph2t up there, I've never tried either or even tried removing steering coils. The way I would try is to just take an exacto blade or a razor blade and try to lightly tap the blade in between the coil and chassis.
Good luck.