Whether you found an old knife in the toolbox or accidentally left it exposed to the rain, the chances are that the blade has rusted. This oxidation layer makes it unusable, ugly and reduces its value; but with a little effort you can restore your favorite pocketknife to its original condition.
Steps
Method 1 of 3: with Natural Solvents
Step 1. Wash it with water
Before removing the rust, make sure the metal is not covered with dust and grease. Just put it under hot running water; proceed slowly and patiently - if you rush things or scrub too hard you risk damaging the blade.
- Use plain water to get rid of dirt or stains.
- Remember to wipe off fingerprint traces, as naturally occurring salt on human skin can oxidize the material.
- Make sure that water does not get into the cracks between the handle and the blade, as this could cause hard-to-reach oxidation spots.
- Thoroughly dry the blade with a soft, clean cloth after washing.
Step 2. Soak it in white vinegar
This liquid contains acetic acid which is often capable of dissolving rust. Dampen a rag with vinegar and apply it directly to the stains or dip the whole object in a bowl full of vinegar to treat stubborn encrustations.
Once the oxidation has dissolved, rinse the metal thoroughly with water to remove all traces of vinegar and then dry it with a clean cloth
Step 3. Apply some lemon juice with salt or baking soda
The juice of this citrus fruit is able to eliminate rust from metal surfaces, but it is even more effective in association with salt or bicarbonate; try using a mixture of these ingredients to remove oxidation from the knife blade.
- Sprinkle some baking soda or salt on the areas affected by the rust, then rub them with a rag soaked in lemon juice.
- After a minute or two, rinse off the cleaning solution with warm water and dry with a clean rag.
- Be careful not to leave any traces of juice on the blade for more than a few minutes, otherwise you could damage it.
Step 4. Use baking soda
It is effective against rust even if you have to apply it several times; it is often used at home and in the kitchen, so you should have some available.
- Make a thick dough by mixing the baking soda with the water. Pour about 50g of powder into a glass bowl and add a drop of water to create a paste, gradually increasing the amount until the mixture reaches the correct consistency to adhere to the surface of the blade.
- Spread the mixture on the knife and let it sit for two to three hours.
- Scrub the surface with a wire brush or fine-grained steel wool to remove stains.
- Rinse off any residue by holding the knife under running water.
- Finally, dry it thoroughly with a clean cloth.
Step 5. Slip the rusty blade into a potato
The raw vegetable is able to eliminate rust from the metal because it contains oxalic acid.
- Plant the knife directly in the tuber and leave it undisturbed for a few hours; after this time, remove it, rinse it from the vegetable juices and dry it with a clean rag.
- Eventually throw the potato away as it may contain bits of rust and is no longer edible.
Step 6. Mix the white vinegar with dish soap
This mixture is effective against rust stains; you can use normal liquid dish detergent and white kitchen vinegar or concentrate.
- Combine one part of detergent with one part of vinegar and spread the mixture on the blade with a soft cloth; then rinse the metal and dry it.
- To treat stubborn stains, soak the blade in the solution for an hour; wash it with running water and dry it with a clean cloth.
Method 2 of 3: with Abrasive Cleaners
Step 1. Scrub the knife with a toothbrush
Use an old one to get rid of the grease, lint and dirt found on all surfaces of the knife; apply some dish soap to the bristles and scrape the metal.
- You can use a fine-tipped cotton swab or toothpick to clean the small areas with detailed decorations.
- After cleaning, rinse off any soap residue and dry the knife with a clean cloth.
Step 2. Try the "magic eraser"
It is a special sponge that removes rust from the blade; no chemicals are needed, just a little water and the "rubber" is ready to use.
Rub the stained areas of the knife, rinse it and dry it with a clean rag
Step 3. Use some steel wool or another abrasive tool
You can scrape off the oxidized scale using a steel wool scourer, fine-grit sandpaper, or a metal brush. You can wipe the blade dry, with a little water or by adding water and dish soap.
- If you don't have a wire brush or sandpaper, try using crumpled aluminum foil.
- Remember to rinse the knife after cleaning and dry it with a clean cloth.
Step 4. Clean the blade with a rotary tool to get rid of stubborn rust deposits
If you don't get any results with the oil or cleaners, try using a tool like the Dremel; work slowly and carefully so as not to damage the blade.
- Smear oil on the rusty metal before grinding it.
- Attach a fine brass brush to the Dremel to remove the rusted surface. Secure the knife in a table vice and gently place the rotating brush with slow and fluid movements on the areas to be treated.
- Change accessory and use a felt wheel; dip it in a polish and rest it on the blade with small, fluid movements.
- Then use a polishing tip and finish everything with a metal paste; rub the knife until it is smooth and shiny.
Method 3 of 3: with Chemical Solvents
Step 1. Use the oil to remove small deposits
Use a light oil, which does not stain or dry metal components; a commercial product, such as the WD-40, is fine for this.
- Use a clean rag to apply a thin layer of oil directly to the blade; use the lowest possible dose because a thick layer can attract dust and debris.
- Leave the knife open and allow the oil to soak into the blade for two or three days; in doing so, the oxidation should loosen and removal becomes easier.
- After this time, use the point of a sharp knife and scrape off the rust with great care; alternatively, you can use steel wool. If you work calmly and carefully, you can remove stains without affecting the finish of the blade.
Step 2. Use a non-toxic solvent
You can purchase a specific rust inhibitor in hardware stores and auto parts stores; this kind of products is more delicate than the acidic ones that are generally used against oxidation stains.
- Pour some solvent into a bucket and submerge the blade.
- Let the product work for half an hour or overnight for the most difficult cases.
- Rinse off the solvent and dry the knife with a clean rag.
Step 3. Apply phosphate-free solvent for stubborn stains
You can find specific solvents on the market that are active against calcium, limescale and rust stains on any metal surface; they are often used on old pipes and appliances, but they are also effective for cleaning oxidation from a knife.
- Dip the blade directly into an equal parts solution of detergent and warm water; be careful not to put the handle in contact with the solvent because it is made of a material other than metal (e.g. plastic, wood, bone or stone).
- Immediately rinse the blade with cold water, do not let it soak for more than two minutes as you could ruin the material.
- If rust persists, use pure (undiluted) solvent and rinse it off immediately with cold water.
- These are typically caustic products, use them in a well-ventilated area and wear gloves.
- Do not mix the solvent with other household cleaners as this could trigger dangerous reactions.
- Do not pour it on galvanized metal as it may cause zinc stains on the coating.
Advice
- To prevent the knife from rusting, check it from time to time and clean it with oil when necessary.
- Do not store the blades in a leather case which can attract moisture and consequently cause the knives to rust; instead, keep them in a special roll of fabric or in a lined briefcase.
