Mine were seeping. I pulled them off, cleaned the mating surfaces (head, both sides of the gasket, valve cover. Wiped a thin, and I do mean thin, layer of Silicone on both sides of the gasket. By thin, I mean I put a dab on my finger, and stretched that dab as far around the gasket as I could, after putting on the layer, I took my finger and wiped most of it off. Let it sit for five minutes (a smoke and a beer), and installed it. No more leaks.
I am a firm believer in silicone, I am also a firm believer that most people use about ten times to much.