Repolishing an old knife blade can add beauty and restore value. Old knives sometimes develop corrosion, rust spots and pits where bacteria can collect. A clean, polished blade requires less force to make smooth, even cuts, preventing injuries. This is particularly important for meat cutters, prep cooks and cannery workers, who have an increased risk of carpal tunnel syndrome.
Soak knife blade in penetrating oil overnight. This will loosen rust and dirt. If the knife handle was made from wood or a synthetic, such as Dymonwood, the handle can be immersed as well, as long as the knife is not antique or collectible. Pat Percival of North Coast Knives recommends using penetrating oil on wood and Dymonwood handles, stating, "Although Dymondwood needs no additional finish, I find that...a penetrating oil finish, brings out a higher gloss" Knife handles made from bone, horn, ivory or antler should not be immersed in penetrating oil, however. According to expert knife maker Jay Fisher, "...care must be taken to keep the handle material clean and dry. Sudden changes in relative humidity...can cause such a variation in moisture content that the material shrinks and cracks away from bolsters, guards, or pins within hours.."
Scrub knife blade with fine steel wool until all visible rust and dirt is removed. Wipe dry with a cleaning rag.
Scrub knife blade a second time with extra fine or 00 steel wool dipped in penetrating oil, until the blade has an even luster.
Use a soft polishing cloth and polishing compound to rub the blade until it is shiny.
Clean the blade with oily nail polish remover and paper towels, changing towels until they come away clean. Spray a paper towel with penetrating oil and wipe the blade to oil it one final time.
20-year veteran blade maker Gypsy Wilburn advises, "This method is not for use on antique or collectible knives. Antique and collectible knives can lose significant value if you use the wrong materials and methods to polish them. Have your knife evaluated by a professional first, and ask for advice on how to proceed."