Our method to raise dents is to use a fine wire gauge drill bit to
drill a series of small holes through the grain of the veneer, into the
substrate.  These small holes will allow steam to penetrate deeper into
the dent and thus cause more than the surface veneer to expand.

We also try to use some method of concentrating the steam to the area.
This helps to minimize surface finish damage.

One gadget we use is a thick brass washer with about a half inch hole
in the middle.  The hole is filled with wet cotton and a hot iron
pressed to the outer surface while the washer is held over the dent.
(Watch your fingers - OUCH!)

On dents in mahogany or other highly reflective/refractive wood
surfaces, try to avoid any opaque wood fillers.  If the dent can't be
completely removed, it can be filled with transparent material, such as
thickened lacquer, shellac sticks, and even instant glue.  These all
will allow the veneers to shine through.

Bob Lemon
Lemon's Player Piano Service
Sacramento, CA