Peel rind off of lemon, leaving some of the white pith. Set aside.
Wash produce with a gentle fruit and veggie cleaner.
Peel the apples and cucumber if desired. Remove core and cut apples into sizes that fit into the juice chute (hopper).
Cut the cucumber and celery into sizes that fit into the juice chute.
Place a cup or juice pitcher under the spout and place a a bowl or pitcher under the spout that dispenses the pulp (if using a compact juicer the pulp may be collected inside the machine).
Turn on machine and begin feeding the fruits and vegetables, beginning with the greens or softer ingredients.
Leave machine on until all juice has been dispensed.
Pour juice into a glass and drink immediately or store in a tightly sealed container for up to 24 hours.
Discard pulp into garbage or compost pile. Pulp may also be used in other healthy recipes within 24 hours.