How do I maintain rubber?
To give your rubber that clean new, jet black look, start by cleaning it with mild soap and water. Follow with a rubber & vinyl protectant or even a silicone-based furniture polish. Do not spray protectants directly on the rubber. Rather, apply it to a damp rag then wipe it on.
Some rubber will naturally bleed paraffin, which will look like hardened candle wax. Use a solvent to carefully remove any visible paraffin.
Rubber contains plasticizers that eventually "evaporate" from rubber, leaving it hardened and cracked. This is a naturally occurring process, but heat, sunlight, smog, chemicals and gasoline/oil can shorten the life of rubber parts.