I use cold wax in my varnish for all of my paintings. It takes awhile to figure out a ratio that you personally like between too shiny and too dull. I use Gamblin cold wax and Gamvar gloss varnish. The Gamblin web site used to have a video showing the mixing process. Gamblin now makes premixed varnish and wax in two sheens other than gloss. But, to be honest I am not brave enough to use the premix because it gets gloppy while sitting on the self.