To release a tiny screw from a threaded partially blind hole — I removed front sight blade from its base on barrel — I put a drop of Kroil® in the hole atop the screw and let it work for a few days to loosen locktite-type material. The screw is so small and its hexhead is so small that I feared stripping the head.
To install a front sight blade and secure it in place, how do I remove all trace of Kroil?