When I was wee we used to recite the following nursery rhyme (Christ knows how these things wash up on the shores of memory, but it just did!).

Ah-choo, ah-choo, me mother has gone to church
She told me not to play with you because you're in the dirt
It's not because you're dirty
It's not because you're clean
It's because you've got the whooping cough and eat margarine

Other 'catters will surely remember rhymes which they used to chant in the playground, nasty or not. It'll be interesting to see whether these rhymes are regional or universal ...