If the basic ingredient is silicone, then screwfix do an excellent brush on liquid silicone sealant remover which might work? Its very cheap, only a couple of quid a pot. Failing that you could do what we did when faces with the same problem and (gently) rub the areas with wire wool.
There is also this stuff
http://www.topoftheli...cone-wax-remover.html
and googling suggests that acetone will do the job but it needs to be real acetone, not the non acetone nail polish remover.
The other thing I have had success with when removing coatings is paint thinners, the king yoy clean Humbrol enamel brushes with.