There's the rotten egg smell and then there's the decaying garbage smell.

What causes the different smells?

 

are you talking about your car? if so, the rotten egg smell is most likely you catalytic converters. i don't know about the decaying garbage smell. the clutch burning is a very synthetic smell, a little bit like overheated brakes.

 

+1 on the catalytics, and burning clutch smells more like burning brakes....
C.

 

Maybe the decaying garbage smell is the remains of that skunk you hit. Hmmmmm. Possibly???

 

If the clutch smell (Decaying garbage or Rotten Egg) was accompanied by the unmistakable clutch response associated with toasting the clutch, then it was the clutch. If the clutch did not have a problem at the time of the smell it is likely the Catalytic converter (or something else).