Hi Devon. Use whatever solvent you have, the Kroil suggested is a favorite. If the cranks are still on the bike, have a trusted friend stand on one pedal in the 6 o'clock position. apply a pedal wrench, preferably w/ a long cheater bar - Park made a round handled pedal wrench which was easily swallowed by readily available steel pipe, to loosen the other pedal a turn or 2 but don't completely remove it. Have your friend stand on the loosened pedal and work the other side. I've had one crank/pedal combo prove impervious to this so i routinely wrap pedal threads w/ plumbers' teflon tape and grease that before insertion. Good luck! Billy Ketchum; Chicago, IL; USA.