Rust is a more severe form of oxidation and results from neglect and prolonged exposure to the environment. Knives that are made from carbon steel are more susceptible to rust due to their high carbon content.
However, it is possible to prevent rust on knives and remove it when it forms.
- Here’s what you need:
- #000 steel wool (or finer)
- Metal polish (e.g. Flitz, Autosol)
- Rubbing Alcohol
- Warm diluted dishwashing liquid
- Non-abrasive polishing cotton cloth/old t-shirts
- Renaissance wax
Removing rust from knives involves some muscle work to polish and scrub out the rust. So, prepare yourself for some hard work! Before you start, ensure that the knife you are working on will not lose its value as a result of removing rust. For some collectible knives (e.g. WWII or ancient swords), removing rust or patina will make them lose their value as these are treasured for their aged look. The rust/tarnish on these knives are best to be kept in check, rather than removed.
- To begin, inspect the knife thoroughly and know what parts to work on. Sounds simple, but the last thing you would want to do is to remove a knife’s logo colour or have cause discolouration of the knife’s handle because of the metal polish.
- Next, scrub the knife down with a warm, diluted solution of dishwashing liquid. This should be done only if your knife is made out of materials that can be submerged in water, such as rubber/micarta and stainless steel. If your knife is particularly valuable or has a leather handle, use a damp cloth soaked with the solution instead.
- After letting the knife dry, wipe it down with rubbing alcohol. This removes any residue dirt/soap and prepares the knife surface for polish.
- Apply the metal polish to the knife surface and to the rusted portion in particular. Leave the polish for awhile to take effect. Note: If your knife is gun-blued, made of damascus or has a coated surface, using metal polish will remove it. Apply with caution!! (Flitz polish is non-abrasive though)
- Using the steel wool, gently work the rusted area in a small, circular motion. Do not apply too much pressure or you may have ugly circular scratches on the knife after you have done.
- Remove the polish using the cotton cloth and polish the surface lightly to remove surface oxidation and bring it to its original factory condition.
- Repeat the previous two steps until the rust has been removed. If the rust has set into the knife for too long, there may be pitting, or little marks, where the rust once was. This is all right as long as the original surface (i.e. steel colour) has been reached and no black tarnish marks remain in the pitting.
- Wipe the knife down with a clean cotton cloth to remove any residue polish that might remain. Then, use the rubbing alcohol to wipe the knife down. You’ll notice that more dirty polish and dirt comes off with the rubbing alcohol.
- The final step is a preventive measure to prevent rust from forming again and slow oxidation. With a small piece of cotton cloth, rub renaissance wax across the blade, forming a visible film. This may not be attractive for knives that are displayed but is the best solution for knives that are kept.
Should you see signs of rust (e.g. Black patches or deep oxidation that does not look like normal tarnish), do not hesitate to remove it with metal polish. With frequent inspection of your knife collection and removing any signs of deep oxidation, you will (hopefully) not see any rust on your knives again.