This article is from the Food Preserving FAQ, by Eric Decker firstname.lastname@example.org with numerous contributions by others.
The term 'scraping the bottom of the barrel' came from potting meat. By the
time the old timers got to the bottom of the pot, the quality of the meat
was often very questionable. And hence the term means even today 'using
something rather undesirable because it is all there is.' (Ref: Leslie E.