Inspect the peg to ensure it's clean. If you have visible dust or dirt, wipe the material away with a damp rag and let it dry before continuing. This helps the repair bond to the peg and last longer.
Rub away any splinters or rough edges from the damaged peg using fine sandpaper.
Apply an epoxy glue to any cracks in the peg or to join two broken pieces of the peg together. Hold the damaged components tightly together as the epoxy dries for at least 15 minutes and wipe any excess away with a rag before it hardens.
Test the peg once it's dry by inserting it into its corresponding hole to see how it fits. If the peg is a bit loose because of the material lost during the break and repair, insert several broken toothpicks into the hole and glue them with the epoxy. This makes the hole smaller so the repaired peg fits in tightly.