I like to drop my freewheels in a gallon tub w/1 liter of diesel fuel & let em soak for a week. Grab them with pliers and shake them. Wear heavy elbow length nitrile gloves & rotate them. Clean the crud off with a toothbrush. Let them dry out. Blow them out with compressed air. Then, drop them in a tub of automatic transmission fluid. Let em soak for a week. Take em out & let em drip dry. & install em.