A big load of gastric worms in WC Monitors will sometimes cause an obstruction and vomitting. Insufficient heat and a big meal (like a rat skull to a small lizard) and they can't metabolize properly and will have food go rancid in the stomach leading to vomitting also. So a detailed accurate report of your overall cage temps and the basking temperature would be good to know. Also what the removed 'spot cleanings' looked like...solid turds or mush? Little white rice things in the poops? Horrific odor of poops?