I've heard brake fluid will dissolve loctite so you might want to give it a try. Other options are to use a hammer driver. With the handheld version you tap on the top with a hammer to either drive in or back out a screw. Depending on screw size you might also be able to use something like an easy out tool. This option would be the least exciting as you have to drill a hole in the top of the screw first to use the tool.