The pet (dog, cat, lizard, etc.) harness is often subjected to abuse that can damage it. Since the nylon webbing used in pet harnesses often contains plastic, it's a good idea to find ways to repair them rather than add them to the waste system.
Nylon Webbing Strap
Standard 1 Flexi Dog Leash Cord Replacement
These are some common tools used to work on this device. You might not need every tool for every procedure.
Metal Spudger
Halberd Spudger
Utility Scissors