Cleaning Out the Tub

There is nothing worse than a little boy in the evening bathtub who all of a sudden stops what he's doing, looks at you, and starts grunting. I immediately yelled "Stop! No pooping in the bathtub/bubbles. Only on the potty!" Too late. Damage done. Bathtime over. Water soiled. Tub must be cleaned/bleached/sanitized/scrubbed/you name it. Eeecch.