Locate glazed or unglazed pottery at yard sales, thrift shops, or a discount store. Hang them off a dock using stainless-steel wire. Let them hang in the saltwater for a couple of months while the barnacles attach and grow. Then pull up the pots, scare all the little crabs away, and immerse the pots in a 5-gallon plastic bucket with granular chlorine for several days. Afterward, carefully remove the pots and use a soft brush and cold water to clean off the mud and loose pieces of shell.
After they air-dry, they’re ready for display indoors. Once indoors, keep the pots in a safe, dry place, as the barnacles are fragile. Dust with a soft cloth.