Finish washing dishes in the appliance if it is in mid-cycle.
Open and lower the door to pull out the bottom rack. Locate the trap in the bottom of the appliance. The part is typically round or shaped like a kidney, with perforated holes.
Twist a round trap counterclockwise and lift. Oval or kidney-shaped traps pull straight up by the tab sticking up from the edge. Remove the trap carefully to avoid spilling food chunks inside the appliance.
Empty the trap into a garbage can.
Scrub the trap with a nylon brush under tap water in the sink until the part is clean.
Reinsert the trap and twist or press to lock it back in place.