1. Screw cleaning scrubby onto the domed end of the cooking tray.
2. Check that the tube has cooled down entirely to room temperature.
3. Pour in a bit of water and some soap.
4. Use the brush end of the tray to plunge the tube clean.
5. If needed, make sure to only twist the tray/scrubby clockwise (from user's point of view).
This will keep the scrubby from unscrewing from the tray while inside the tube!
However, if you do get yours stuck at the end of the tube from turning in counterclockwise, just shake the tube until it dislodges, or place a soft towel over an unbent metal coathanger, and carefully try to scoop it back out.