Question About Rubber Jeep Tires

My son and I are detailing a GI Joe-size (1:6th scale) WWII jeep, including mounting a DID .50 cal on a resin M-31 mount.  The rubber (or rubber-like vinyl) tires are much too shiny.  Does anyone know a way to remove the shine from the tires before applying dirt and dust, or would the dust take the shine down by itself?  I thought maybe soaking them in some kind of solution would do that, but not sure what to use and I don't want to destroy them by accident.