Had to break one of the containers to be able to use the blades on the other container. It was stuck. Problem one solved by pouring cold, boiling, cold, boiling water over it until the plastic container cracked. Then I smashed it into the sink several times until the black thing with the blades came loose. I would like to have at least 4 or five containers so i can have smooooooth shakes instead of clumpy ones...