Speaking of sheep, an anti-abortion fanatic by the name of Horsley (or was that Horsely?) recently confessed -on live radio- to having "relations" with farm animals specifically mules but also others unspecified. You can find transcripts and/or tapes of the audio online.
Okay, so the auction was pulled. I'll guess it was for (hmm, how to say this delicately and in G-rated terms?) unwashed underwear that has been worn longer than usual by someone whose personal hygiene habits in the toilet are less than ideal.
In Japan, there are vending machines in public places that sell underwear worn by highschool girls (presumably of average hygenic habits), for the "entertainment" of men who in my opinion are rather warped.
Re. "skid marks" and suchlike: I've never had them (as in, not even once), and don't see any reason why anyone would, unless they're trying to economize too much on toilet paper

. If someone has a sudden onset of a terrible tummy problem, the results could be taken care of via an immediate wash in a bucket of soapy water, followed by a bleach rinse, followed by a clear-water rinse.
Re. reusable feminine pads: I suspect these could end up making a comeback. Good reason for someone to invent a 1-lb capacity fully automatic micro-washer with a bleach dispenser and internal heater. That would also take care of underwear...
Someone mentioned pillowcases. Hmm, time for a new topic...