I am going to making a few calls for a group of us heading on a hunt this spring.They will be doublesided,glass over slate.I am going to have some artwork laser engraved on the underside of the glass,the area of the glass where the striker touches,what is the best way to condition that area.I have only used blasted glass for calls,this needs to be clear due to the design on the glass.Etetch cream then sand?