Here's a way to install valve and pushrod covers and oil pans so that they can be easily removed and reinstalled without installing a new gasket and cleaning only 1 contact face. Make sure that all the gasket surfaces are clean and dry. Apply a small bead of RTV to ONLY the surface that you want the gasket to permanently stick to. Put the cover in place and snug the bolts down. I install a couple of Pilot bolts to keep the gasket aligned and the cover from slipping around during fit up. After the RTV has set, take the cover off, then wipe on an oil film to the entire exposed side of the gasket. Apply a bead of RTV to the clean cover surface and reinstall the cover. The RTV will fill all voids for a leak tite seal but not stick to the gasket. Once cured, the cover can be removed with a slight tap and the RTV will come off with the cover and the gasket surface will remain as good as new. Of course, the RTV will have to be removed from the cover and reapplied, but that's easy. Did it twice on my valve cover and not a leak was seen.