Tip:
I use this to maintain my tires shiny and "wet" to prevent dry rott. It even restores them by making them soft again, it will not seal cracks, but it will hide them to a degree.
It is: CRC Industrial Food Grade Silicone Spray Part.# 03040
I even use it to spray all over my chassis and plastics, works excellent as rust preventer and plastic restorer. Oh and it leaves NO residue
