Sanding through hardwood veneer is a woodworker's worst nightmare. But you can bounce back without much difficulty. Just use a trick professionals use but don't talk about. You can disguise a veneer sand through without a time-consuming inlay. All you need is an assortment of stain crayons and a X-acto knife. An X-acto knife is a craft knife with a very fine point. Using these items and your artistic talents, you can fix almost any missing veneer.
Cut a grain pattern into the sanded through area. Use the tip of the X-acto knife to surgically cut as you draw a very light grain pattern into the sanded out area. Cut about 1/64 inch deep. Curve the cut lines or add swirls to mimic the grain of the existing wood.
Draw over the cut lines with the stain crayon, forcing the crayon residue into the cuts.
Dampen the cloth with stain. Thoroughly rub over the area removing all signs of crayon with the stain-dampened cloth. The grain pattern should still have crayon residue in it. The cut-out grain should now resemble the existing grain.
Sand over the area lightly by hand with 180 grit sandpaper. Apply more stain to the area with the cloth. Dampen it completely and let it set for five minutes for the stain to soak in.
Wipe off the stain. Examine the colour. If not dark enough, apply more stain and let set another five minutes or until the sanded area is the same colour as the existing wood. If too dark, lightly sand with 180 grit paper, apply more stain, and wipe off immediately to prevent the stain from soaking in.
Experiment with different colours of crayons on an area of the wood that can't be seen. Sometimes the colours look different when they are applied to the wood. Stain crayons, pencils, markers and X-acto knives can be found at any home improvement store.
Don't cut too deep when drawing your grain back in. Just enough to pick up the crayon.