Do you "treat" your speakers rubber surrounds?


I was wondering if anyone out there puts any products on their speakers rubber surrounds? I notice that mine get dusty from time to time under the grills, so I do dust them. I am wondering if perhaps they could benefit from having some type of "moistening" product put on them.

Thanks for your input,
I've seen too many speakers with rubber surrounds from the 70's that look and work fine, maybe better.
Armour-All deadened the sound of a low value test speaker once. It had foam rubber surrounds, but still the effect was large and not good. I would stay away from anything with silicon.
I would say don't put anything on foam. Rubber however can dry out and crack due to environment and age. I see nothing wrong with treating rubber surrounds with something that will protect, lubricate and repel moisture and dirt. Sounds like this 303 may be worth a shot. After all our skin likes to be well lubricated to maintain its elasticity.