cat box smells like an ash tray?

this is really weird because neither my roommate or i smoke.  but the cat box (or that one particular corner of the house) smells like an ash tray.  i've never seen a cat smoke a cigarette, haha.

Which litter are you using?

it's called Cat's Pride.  roommate bought it, and i'm not sure where from (probably walmart though).  do you think it's the litter?

I use Cat's Pride Unscented Scoopable and flushable litter. It smells like clay/dirt to me.

i figured out the problem.  it isn't the box that smells like an ash tray, it's the garbage can i'm scooping the litter into.  my roommate's new girlfriend smokes, and even though she smokes outside, she's a decent enough human to throw her butts in the garbage.  hence the garbage smells like an ash tray.