I've used 99% isopropyl alcohol. There is Kodak pdf sheet floating around the internet regarding film cleaning. They advise that the safest thing for the film is isopropyl alcohol of 98% or higher. A lower percentage contains too much water which soaks into the emulsion.
I figured I would just try it as I didn't have any of the special liquids, and it works just fine.
I've only done it this way, so I have no idea how other products may be better. It is cheap, and it doesn't smell bad, so it is kind of ideal in that sense.