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A tip for covering scratches on dark furniture - Using a partially green walnut husk, simply rub the scratch until you're satisfied with the darkening effect. Now apply furniture polish to the entire piece, and the scratch will be gone. (I also suggest wearing rubber gloves to avoid staining your fingers with the walnut dye.)
By Eulice
An antique dealer told me this useful trade secret for covering up light scratches on dark wood furniture. Take a shelled walnut and rub it along the scratch several times, then wax or polish as normal and rub to a shine.