I have only cleaned out the bottom of my UDS one time in the past year. Everything comes out with the ash pan or is burnt up in the charcoal. I add new charcoal and clean off the ash pan before each cook. No grease to clean up in the bottom of my UDS. It stays clean.
Ash pan is a 20" harrow disk.
Performer, UDS, 2011 WSM, Frank-in-Weber, 120 Gallon Offset, IQ-110, ET-732