A bit of an easy concept, but still a great one.

The common reason why anyone would wash their hands or use hand sanitizer is to prevent the spread of germs from other people onto yourself.  So, with a hand sanitizer, there is really know other way to go in advertising and campaigning for it.  However, this ad and the whole campaign does a great job of translating this in a funny and clever way that has the stopping power to make you read and understand it.  I tried to look up some other sanitizers, like Purell, to see a comparison and the concept is pretty much the same, but they are not executed in as clever and humorous of a way as these are.