I learned this one from a coworker, but have since found it out on the Internet too. I stole the idea for pigs clean on one side and dirty on the other from Miss Mary Liberry!
Five Pigs So Squeaky Clean
Sing it to “Five Green and Speckled Frogs”
Five pigs so squeaky clean
Cleanest you’ve ever seen
Wanted to go outside and play
One jumped into the mud
Landed with a big thud
Then there were four clean squeaky pigs.
(Ed. 11/11: I am no longer sharing my clip art files due to copyright concerns, so I’ve taken down the link to the files. This pig is no longer in Microsoft Word clip art, which is where I originally found it, but you may find another clip art pig that would work as well.)