I haven't tried to search for it, however, years back in Thumper Talk the prescribed prevention was: 1. Keep the appropriate size/thread tap handy to use each time you drain the filter 2. Coat it with grease to hold the foreign material, fillings, etc. that the filter trapped and followed the oil down the drain hole. 3. Turn it in with your fingers to clean the threads after the oil is drained. This procedure has protected all all four YZ's in my history. Should this be a sticky? If you follow my recommendations as to removing the lower bolt last, instead of first, and let the filter oil drop out of the cover rather than through the threads, chasing the threads is rarely required. If it is, I find that a cotton swab dipped in clean solvent works as well as a tap, if not better, as long as there is no thread damage to repair. Push it straight in, then "thread" it out. One other thing to note is that once a Time-Sert is installed in that hole, the source of the problem will be gone, because the cross hole that lets oil into the threads will be blocked by the insert.