Prothane's Super Grease was designed specifically for their bushings, to prevent the polyurethane from squeaking. This stuff is sticky, and we mean sticky. We at DST recommend that you wear latex gloves when applying the grease, because it is very tough to remove. If you think it would be difficult getting this stuff off of your hands, getting the grease off your bushings is even harder.
Prothane's Super Grease is a PTFE, water-proof lube that clings to the polyurethane. Meaning it isn't coming off without a lot of soap and a ton of scrubbing. Not only is this grease waterproof, but it's also heat proof, making it an ideal suitor for Prothane's bushings.