What food waste cannot go in the machine?

The food items which may not be placed in the machine are oyster and mussel shells, corn husk and pineapple tops. The reason for shells not being able to go into the Pulpmaster machine is because it grinds up into sand which overtime will build up and block the pipes. The reason corn husk, pineapple tops and lemon grass can’t be processed is because this material is very fibrous and if put in the machine it will form a hairball like product which will get caught in the chamber resulting in a blockage, stopping all other food waste from being processed.