I can not think of any way to apply it to the valve seats in enough concentration if at all. Both exhaust or intake. One poster mentioned it helps some things by introducing it into the fuel tank. I still wish I knew what this stuff is. A lot of people seem to have experienced positive results. The product has always been marketed as long as I can remember. I suspect it is not snake oil.The newer penatrating oils have a strong acid base. Perhaps this product is an earlier version of them?