I accidentally left some tools outside for a few days while I was away and they rusted. I can barely use them now. They were good tools, and I don't want to have to buy new ones. Is there any way to get the rust off of tools and return the tools to close to the state they were in before?
There are a few good options for this
This is slower, but works really well. Soak the tools in white vinegar for about 24 hours. Most of the rust will come off, and the rest will easily come of by scraping it.
Mix baking soda with water until a paste that you can apply on the tool. Use a toothbrush to scrub off the baking soda. Then rinse with water.
Soak the tool in diesel for 24 hours. You can use a brass brush after it is done soaking. Clean it with an old rag after.
I think the absolute definitive way to do it is with electrolysis. This is where you place the rusty component in an electrolytic solution (can be water with a salt dissolved in it) and run a current through the rusty piece and a "sacrificial" piece of metal via the solution. It works similarly to electroplating but instead of depositing a coating on a metal, it removes the rust. I've never done it and I think it's a bit of an effort to set up the first time, but after you've made a rig to do it, it's the most effective way.
I wouldn't set this up if I had just one piece to do, but if I had say 5 items to do and they were fairly rusty then I probably would. One of the major benefits is that this can be used for VERY rusty tools, cast iron pans, etc. and does not damage the "healthy" metal underneath the rust. It also doesn't require any harsh chemicals or hard scrubbing.
There's an example here http://www.instructables.com/id/Electrolytic-Rust-Removal-aka-Magic/ but if you search for "electrolysis rust removal" (without quotes) or similar on google then you'll find tons of results.
I believe that after using this (or any) method, you should dry the items thoroughly (in a warm oven can be a good way, though not if there are wood/plastic parts) and oil them to protect from further rusting. This is especially important if working on cast iron (use vegetable oil if the items are cooking utensils/pans) as this will rust very quickly if not dried out and protected.
Use a wire-brush or if the Surface is sensible use brass-brush.
then if is not enough
i use a Product from Hammerite. Is the best i have used yet. It's a Paste. They also have a liquid for immersing the rusted parts. It's a good product becuase it is no rust-inverter, like the most other available products and thats mostly not desired.
also it is not too aggressive. the only drawback is the (steel) parts be a little mat.
I heard You can clean using coke. http://youtu.be/z7OdX42NjWQ
@michaelpri, @subjectivist - Thank you and I will remember to write better answers from the next time.
I obtained a great collection of hand tools from a retired car mechanic. Ratchets, sockets, swivel sockets, pry bars with ratchet adapters, extensions, impact sockets, wrenches, screwdrivers, etc. A number of them snap-on and craftsmans, prontos, Napa, etc. Most had medium rust, some heavy rust. Because of the sheer volume of tools I didn't use evaporust, etc, due to the cost. The best and most cost effective method was white vinegar and then 1 cup of baking soda per gallon of water. Let the tools soak, completely covered, in the white vinegar. 24 hours if not too bad, 48 or even 72 if very bad. Then scrub with brass wire toothbrush. Pull and Dip in water to rinse then into baking soda paste. 5 or 10 minutes. Pull and scrub with 0000 steel wool. Wipe down with rag soaked in mineral oil. Coat with coconut oil or a corrosion proofing spray.
First use Sand paper to remove the rust first then clean it with brush using toothpaste. You can also try using kerosene or diesel !!
I use a liquid product called Concrete Prep which is used to etch concrete cracks before patching them with fresh concrete. It is actually phosphoric acid and does an extremely thorough job eating rust off of steel tools. If you soak a rusty thread-cutting tap in this stuff overnight, it will come out atomistically clean in the morning (just briefly scrub with soap and water to remove the iron phosphate).
Provided the tool can be submerged, Evapo-Rust is one of the best, and most environmentally friendly, ways to remove rust, as it utilizes microbes to eat the rust.
All metallic tools should be thoroughly cleaned and coated in oil (such as WD-40) after use to prevent oxidation.
I use WD40. With pliers, spray a good bit then work back and forth until fully loosened up. Rub with a rag with WD40. Makes it like new and will protect.
I second the solution for electrolysis. The only problem with that is you need a good voltage source of at least 4 volts (12 would be better), or a current source of at least 1 amp. It will be very slow if your power is limited. And I wouldn't bother finding the cleaners that are suggested on the internet. If you are doing one job, use whatever you have at home. Anything from baking soda to lye is acceptable. (For reference, 0.5% concentration of lye in water does not cause significant irritation to your skin, at least not in a short time. You can search online for "naoh irritant concentration" for more information.)
If you find this slow process annoying, you can pickle it with an acid. HCl is cheap and available. Soak it in HCl for a while, quickly rinse it and get it covered in a dilute base to neutralize the remaining acid, rinse it in water, and scrub it with a wire brush. Dry it at a high temperature, but I don't advise using a flame.
With either process, it will rust as you're wire-brushing it before it dries, but the bigget danger is leaving acid on it in the open air for more than a few moments.
3-in-one oil is great for unsticking rusted tools. Unlike WD-40, it is actually a lubricant so it won't dry up. WD-40 is neither a lubricant or a penetrating oil.
Pour a tiny bit into the joint of your pliers and slowly work them back and forth until they become loose again. To remove the surface rust, apply some of the oil to a steel wool pad and rub on the rusty parts until clean. This oil will help "kill" off the rust and prevent it from rusting in the future.
Electrolysis tank is the absolute best answer. I found a pair of needlenose pliers in the ground when I was digging a fence post and used electrolysis on them. They work like new and instead of removing metal, it adds metal back to the pliers. It's not hard to set up, just grab some baking soda or detergent booster from the grocery store for a few dollars and use a car battery for the power source. You can use a small container or even a gallon sized freezer bag!! And voila, brand new pliers.
Scrunch up some aluminium cooking foil into a ball and then rub the rusty surfaces.
Plate (grey phosphate, gun bluing, black oxide, etc.) and/or oil after derusting to keep from rusting again.
