Just take a little off the top

To avoid running a delicate piece, such as inlay, through a potentially destructive planer, I found a good way to safely secure the piece while sanding it to thickness. I clamp a scrap piece of plywood to the workbench and rout a recess as deep as the final workpiece thickness, and to roughly the shape. I can then drop the piece into the recess and sand or scrape the piece until it is even with the surface of the plywood scrap.
—Rick DeFazio, North Olmsted, Ohio