Gather terra-cotta pots with simple, clean lines—smaller ones to hold votives, and larger vessels for flower arrangements.
Press air-dry clay into the silicone molds, scraping off any excess with a plastic knife so the clay is flush with each mold.
After a couple of minutes, while the clay is still wet, gently flex the mold and pull out the accent—use a toothpick to help wiggle out any stubborn edges. With the vase on its side, attach the embellishment with craft glue, curving it to the surface. Let harden completely overnight. If using the pot to hold flowers, line it with a vase or plastic bag to prevent leaks.