My cat's messes tend to be on her own back end, so cleaning them up requires chasing her down and holding her under the faucet. Luckily, she's fairly cooperative (especially for a cat!) about being held under the faucet.

I am currently tragically catless, because my cat moved in with my fiancee on Sunday and I don't get to move in with her until tomorrow. I am suffering extreme kitty withdrawal right now.