Tuning with jets, Power valves and an O2 guage

Are you saying to clean all of the oil and grease off the valve cover gasket mating surface before you adhesive seal the gasket to the valve cover? Sorry, just a little confused with the sentence structure.

I'm talking about the valve covers... Not the intake. I don't use paper gaskets and do use a little ultra grey or ultra black around the ports. I've never had an issue that way.