Done and dusted
Posted by Bruce Kahl on May 18, 2000
In Reply to: Done and dusted posted by Julian Henderson on May 18, 2000
From looking at a couple dozen web sites with your phrase as the search target, I would guess that the term means "finished with" or "completely done".
Just a guess, but maybe it is a housekeeping term--put away the junk etc. and then get out the vacuum cleaner so you can say that the house has been "done and dusted"!
Maybe it is a law enforcement term describing a crime scene after the forensic people finished dusting for prints.