I like to use plain packing paper (can pick up a pack of about 150 sheets at Home Depot for around $10).

No spot cleaning, just throw the paper, disinfect the tub (I use Chlorhexedine diluted with water in a spray bottle), wash the bowls and hides (if you use them), and you are done.

If there is a really bad mess; I will rinse the tub out in the bathtub first.