i'm not sure if this will work on rubber but it does an amasing job on vinyl, i tried to remove the XR off an old motorcycle seat that had been out in the sun for years, the XR didnt remove but the seat became soft as new, i use it all the time now on old vinyl, spray it on and wipe it in with a rag, soft as ****er and lasts for years, well it never did get hard again and i owned the bike for ten years.
Go to your favorite drug store, buy a bottle of Winter Green liquid, mix with water and boil (outside), makes stiff rubber ply able again and smells good to!
The Jalopy Journal
