I have that album with the Grant Brothers recording: "My Rough and Rowdy Ways, Vol. 1," Yazoo 2039, 1998. Some time ago I tried to transcribe it, and I had trouble on the same 2 lines you did, Allan C—here's what I guessed the words were:

Sniff cocaine on a corncob (?) knife.
Sniff cocaine if it takes my life.

All you rounders think you're tough,
Feed your women on Brewer's (?) snuff.