Originally Posted by sinking
On my C5 Corvette the weather stripping around the windshield and back glass is a hard rubber, shiny, nonporous material. It has an oxidized look to it now from the Texas sun. Is there a procedure to help restore this at least somewhat until I can get around to replacing them? Since it isn't porous it doesn't seem to take to rubber and vinyl protectant well and if I get compound on them the oxidization seems to just collect it so I haven't tried really polishing it with compound.
That "hard rubber" is probably made of EPDM...a "synthetic rubber". GM recommends using Dielectric Silicone Grease [GM US Part No. 12345579 (from my Corvette owner's manual, pg. 444)]
Dielectric silicone grease ( not really "grease") is a synthetic (man-made) lubricant ideal for synthetic (man-made) EPDM rubber.
I just apply a very light coating...wait a few minutes...gently wipe away excess...repeat as necessary. It also helps reduce some "squeaks", sometimes.
You can buy dielectric silicone grease, tube or spray version at most auto parts supply stores.