When I did bodywork/collision repair, I would come home filthy with bondo dust. The guys in the paint shop preparing the cars for paint get plenty dirty as well. The buffers get covered in buffing compound. And when I did frame repair, I crawled under those greasy cars all day long. The thing with bodywork is that all the spit, crap, urine, dead varmints and everything else are in the road and your tires kick it up into the undercarriage of the car. So I think collision repair is a dirty job. On a second note, I haven't seen you do mechanic's work other than at the junkyard. It would be nice to see you become a mechanic. Third and lastly, I've learned some machining over the years and it seems like a fairly oily grimey job to me.