Excellent advice Tom.  One step further, Luthiers take scraps of the various
woods they use and make sawdust and store it in envelopes.  Knowing that the
color always darkens when adding the various liquids, they pick a lighter
colored sawdust that will match the work piece.  A rasp or course file gets you
there in a hurry.  Also a fine line magic marker (.05 mm or less) in the right
color can make convincing grain pattern across a small defect.

Ed Minch