Treatment for rubber speaker surrounds?

Nsgarch..."enough frivolity"? You must be on the wrong website!

But if you insist...the "really early rubber-impregnated cloth and the corrugated paper types" actually work very well for drivers that do not require large excursion, or low free air resonant frequency, and, in my experience, seem to last forever. I have never had a problem with anything other than foam.

Eldartford -- OK, you win the frivolity run-offs!
And I agree, there's nothing wrong with the older designs. In fact a lot of dome tweeters simply mold the dome and "surround" out of the same material for exactly the reasons you mention.

The problem with foam is it's not very resistant to the elements. It's fine when protected. for example, when you remove a speaker from the cabinet, the foam compression gasket is always in good shape. I have a friend in Hawaii who had to replace the foam surrounds on his JBL's every 30 months on a regular basis. They just rotted away in the heat and humidity!

I hope I didn't imply that one should get anything wet. A barely damp piece of towelling with some nap is all you need to remove dust, and will not harm paper cones. It doesn't hurt to blow them off first with compressed air like DustOff. Sometimes that's enough. Just make sure you keep the nozzle at least a foot away.

Here is what you want. I used to rebuild and restore inflatable boats - and this is the ONLY product to use on rubber. You can get samples from the company absolutely free. No kidding:

http://www.303products.com/main.php?infopage=freesample