Preserve old treasures and create a useful gift in the process.
If you don't have broken pottery, place chipped, leftover tiles in a clear plastic bag (this way you can see what you're smashing) and break them with a hammer. Another good source for broken tiles is your local tile or hardware store; many will give you broken display tiles for free.
Cover the work area with newspaper. Before starting to decorate the pot, sort through the pottery pieces and discard any that have sharp edges (a parent's job).
Spread a heavy layer of tile grout onto the flowerpot with the plastic knife. Then press the tile pieces into the wet grout. When finished, spread a little more grout between the pieces so that most of the broken edges are covered.
After the pot is dry, wipe off any grout film with a damp sponge.