While it is common for people to use plastic pellets as a filler it is critical that you do not use too many. It is necessary for rocks to rub and grind on other hard surfaces so using too many plastic pellets can slow down your tumbling process. We suggest using no more than 1/4 of a barrel of pellets at any time. While Plastic Pellets are reusable, they can get contaminated so be sure to use different pellets in the polish stage than you used in the pre-polish stage. While plastics can be used with success
in rotary tumblers, it is not that helpful in vibratory tumblers as it can spend most of its time stuck to the sides or the top of the tumbler. It is our opinion that ceramic media is a better option than using plastic in any
tumbler.