I don't know if this is the "correct" way, but I wipe mine out with a damp paper towel and the spray all over inside with a mild bleach solution and leave it open to air. I also soak all of my trays in the tub about 1/2 full with a few cups (over kill I know) of bleach and rinse VERY well. Spray solution is about 1 q. water to about 1/2 TB of bleach. If I had little pieces of egg shell WAY in the back I couldn't get out by wiping, I've stuck my vacuum hose down there to suck them out, then wiped & sprayed. Make sure to wash & disinfect your humidity tray and humidity sponges too.
