One trick is a few tiny drops of CA glue. I place snug fitting wooden dowels in the rivet/screw holes and push them out when the sanding and polishing is done. Obviously, don't put the CA near the dowels. When ready to remove the scales, place in the freezer and when cold push out the dowels, and give it a light tap from the side with a nylon mallet or piece of soft wood.
The normal method of attaching ivory scales is to use screws or bolts. If using Corby bolts, make up a pair that has slots cut to fit a screw driver. When ready for glue up, unscrew them and replace with a new pair. After the epoxy is cured, carefully trim them to flush and sand.
If using screws, remove the ones used during the sanding, and replace with new screws for final assembly. This will assure clean and bright screw heads. I often counter-bore the seats a bit high for the screws, and adjust them to a perfect depth during or after the sanding. When the screw heads are at different depths, it sticks out badly.
Tips:
Place two pieces of printer paper under each scale when doing the sanding and finishing. Discard after the fitting is done.The paper will compensate for the glue thickness in the final assembly. This works especially well with Corby rivets. You may have to experiment with the number of sheets of paper to match your glue line thickness.
Tape off the bolsters and blade when doing the final glue up and rivet finishing.
Wax the bolster and tang edge with some Renaissance wax or other wax. This will prevent any epoxy excess from bonding on those areas and make clean up simple.
Wipe the epoxy off the tang edge and bolster before it fully sets, and clean with acetone when set, but not cured. This will eliminate a lot of problems later on.
