Word of the day: Effluvium.

ef·flu·vi·um (-flv-m)
n. pl. ef·flu·vi·a (-v-) or ef·flu·vi·ums
1. A usually invisible emanation or exhalation, as of vapor or gas.
a. A byproduct or residue; waste.
b. The odorous fumes given off by waste or decaying matter.
3. An impalpable emanation; an aura.
[Latin, from effluere, to flow out; see effluent.]

From http://www.thefreedictionary.com/effluvium

Example: Herman Cain talked about "used food" at the Republican debate. I thought that "used food" was a euphemism for the effluvium that tends to emanate from Republican candidates' mouths most of the time.