Besides cutting them off at the base of each antler you can do it this way. Come out a few inches from the base of each antler and use a hacksaw and cut through the skull, hide and all. Cut completely through the skull bone all the way around both antlers so when you lift both antlers thier held together by the bone of the skull. Clean any flesh off. If you want to keep the hide on you have to treat it so it tans and doesn’t shrink. If you want to take it off, then just clean the skull base again by boiling it and removing the rest of the flesh. Then you can mount it to a plaque. Maybe someone else can chime in and give thier ideas.