These are cleaning pellets, made from a woollen cleaning felt, and are a purely natural product containing no chemicals! Just pop one in you barrel (Maybe put a pellet behind), close it up!, and pull the trigger, that simple. It will clean your barrel of all sorts of nasties. These are very absorbent and can trap large and small particles of dirt in their tangled fibre structure. They do actually recommend a pellet behind these cleaning pellets in a spring air rifle!!