i plumbed the elbow drain on the side of the collection cup to the
sewer line in my house. then drilled a hole in the lid of the cup. i
ran some 1/4 tube in the hole. it goes through the lid & into a 90
degree elbow (john guest fitting) & then in to a T fitting. i created
a closed loop with the remaining 2 connections in the T fitting & in
the tubing of that loop & punched holes with a thumb tack. then
attached a 120v solenoid to a timer. now once a day for 1 minute it
sprays the cup clean & all the crud washes down the sewer line. i
still clean in throat about every 3 weeks.

i read somewhere else of a guy who ran the waste output of his RO
filter in to his collection cup to wash it out.