This little gem came out of my Harry Potter obsession. Plastic cauldrons are easy to find during Halloween and St. Patrick's Day.
Gather your supplies (marbles not shown).
Cut a circle about twice the size of the cauldron out of the fabric. Stitch a straight running stitch around the outside.
Pull the running stitch up about half way to gather the fabric circle.
Add weights to the bottom of the cauldron, top with polyfil. Add polyfil to the fabric circle, pull thread tight.
Squeeze hot melt glue under the lip of the cauldron. Push fabric into the cauldron, making sure it catches under the lip.