My buddy is giving me an 86cr125 that needs a clutch and a retap on the oil drain plug. I figure ill put a heli coil in it. I have a basic understanding on how to do it, but how do you keep all those metal pieces out of the bottom end? I read somewhere that putting a small rag in there, then when you pull it out it should pull the pieces out. Does this work? Also will i need to buy a std bolt of the heli coil or will the stock metric one work?