Sure. If you wish to save the juice, just push the carto down into the tank (with the tank tool on the cart) just like you would to refill the tank. But now, just turn the tank upside down and allow it to empty its contents into a container. I use the little medicine cups used for cough syrup measurement.
Put the un-used juice from that back into the original juice container. The carto can then be pulled the rest of the way out of the tank and discarded. Rinse the tank out under a faucet and shake it dry. Ready to start fresh with a new carto.