I am turning a shift knob for my antique car. I am inlaying a half dollar piece on the top. I turned the inlay slightly larger than the diameter of the coin in order to fill it with something that may seal the end and smooth the transition from wood to coin. I plan to finish this with shellawax because I would like to see the knob burnish a little over time. The wood is Mahagony. I dont know if something clear like CA or maybe a black acrylic will work best, or just let wax build up in there. ( the later probably not a good idea ) Your comments and knowledge would be a great help. I dont want to screw this up.