Used as a code word over the phone when talking about marijuana cigarettes, joints, reefers, doobies, chongers, etc., etc....
Hey man do you got any rusty mufflers?
by stoner July 17, 2002
Feces left around the anus. The situation one finds oneself in when, having defecated, one finds that there is no toilet paper available.
I had a crap this morning, but there wasn't any bumwad, so I had to go all day with a rusty muffler.
by king dude January 24, 2005
Giving a rim job to some one that still has shit on their ass.
Did you see Stevie Wonder at the Democratic National Convention? He totally gave someone a Rusty Muffler.
by Kenny Young August 28, 2008