OK - I'm betting you are up against 3-in-one oil. You will need brake cleaner or some kind of xylene product. Carefully spray a little brake cleaner in a tin can (anything plastic or paint will vaporize). Then get an artist brush made of hair. Brush the brake cleaner on the grooves and the little plate that goes in and out of the grooves. Protect your painted areas. VERY careful - do it out doors or garage run a vent fan - the brake cleaner should vaporize the gunk. You will only use a few drops of it. Pouring rubbing alcohol in there isn't a real good idea.