I'd also suggest wax. I have fixed this exact problem this way. I'd use
a dark wax, applied with 0000 steel wool. It is your option how much
sheen you want. The more you steel wool it the more you will knock down
the sheen. Then just buff it to the sheen you want witha cloth. Of
course a little wax goes a long way so don't use much or the surface
will keep finger prints way to easy.

Test these before trying on real work:::
Another thought is to try washing it with mineral spirits or some other
solvent that won't disolve the shellac. I'm not actually sure that MS
won't dissolve it but I'm sure there is some solvent that would work.

Another idea is to very lightly wet a cloth with alcohol and quickly
wipe/buff the piece.

Another idea is something like Murphy's oil soap.