I do plan to put out a piece of paper "Cash only. Exact change only." I'm not there to be a banker, I'll tell somebody to go buy a hot-dog if need be to get proper change.
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
This
Price your stuff reasonably. Accept no offers or trades.
It'll move.
When I worked at the LGS we would take all the slow movers to the gun show, set up a table and price them to sell. They always did.