Why do flies rub their front feet together?

Question

I was just watching a fly and it rubed its front feet together, why?

Answer 1

..i think he covered all the bases .. thats a good answer.

Answer 2

Flies constantly clean themselves, and their feet are used for tasting.  If the fly lands on something it likes, it will extend its proboscis to get a better taste.

The fly you observed could be cleaning its feet, its eyes (which have no eyelids), or its mouthparts.