Going back to the ability of handcrafted items to pick up the vibes of people touching them, I have found that using my singing bowl nearby cleanses things for me.
Having a market stall in a tourist town is fraught with the dangers of insensitive people handling the goods. I mix my goods with antiques, reproduction items, and lots of curios, all of which have a "past" which seems to protect the handmade stuff.
Protecting myself, as an empath, is more difficult, but there are ways and means.