Use Denatured Alcohol. Safer Than Gasoline And Doesn't Have Affatives That Can Attraet Dirt And Get Sticky
Honestly... unless you have very good bearings, the best thing youc an do is toss them and get a new set. Most bearings are inexpensive and rather cheaply made. If you are using something like bones swiss, then take care of them and they can last for years. What do I use to clear my swisses? Gasoline. Its dangerous, but nothing works better. Honestly, just get a new set if you are riding cheap bearings.