The term ghetto comes to mind every time I hear or read about someone, somewhere, who has miraculously removed rust from metal parts using nothing more than a can of soda. That’s right... the same refreshing beverage you probably have lying around in your fridge. As preposterous as it sounds, this urban legend had me second-guessing myself and made me wonder: Does this stuff really work? After hearing fascinating stories for the 100th time about someone’s brother’s mother’s sister having amazing success with a can of soda, it brought me around to finally test the myth with my own controlled experiment and find out for myself if it truly works. Perhaps there’s some secret ingredient in soda that will react with iron oxide (rust) that removes it? We’re soon to find out!
Soda Facts or Fiction You be the Judge
1. In many states in the United States, the highway patrol carries two gallons of soda in the trunk to remove blood from the highway after a car accident.
2. To clean corrosion from car battery terminals: Pour a can of soda over the terminals and it will bubble away the corrosion.
3. To clean a toilet: Pour a can of soda into the toilet bowl and let it sit for one hour, then flush clean. The acid in soda also removes stains from fine dining chinaware.
4. To remove rust spots from chrome car bumpers: Rub the bumper with a crumpled-up piece of aluminum foil dipped in soda.
6. To loosen a rusted bolt: Apply a cloth soaked in soda to the rusted bolt for several minutes.
7. To remove grease from clothes: Empty a can of soda into a load of oil-stained clothes, add detergent, and run through a regular cycle. The soda will help loosen grease stains.
Soda Rust Removal Test
To test if a soda’s acid can truly dissolve rust, we gathered up a set of used head studs from an old Subaru EJ20 engine sitting around in the garage. The head studs were heavily oxidized with rust and residue. To begin our experiment, we placed the rusted head studs in a half-cut can filled with soda and left it alone for a few days while monitoring its progress.
Day 7: No change besides a slimy residue beginning to form. We replaced the soda with a new batch and continued the process.
Day 15: Head studs look visibly worse, but now have a hazy sugarcoating similar to rock candy. We threw away the soda and called off the experiment.
Metal Rescue: Rust Remover Bath
Rather than waste more time experimenting with various soft drinks, we decided to take the more sensible approach and test a new rust removal solution called Metal Rescue, a water-based, biodegradable, rust removal solution that has been receiving praise across the automotive community since its debut at SEMA 2010. Metal Rescue Rust Remover reps claim their formula was developed for use on iron and steel and removes rust from metal, but will not harm other materials such as wood, glass, rubber, vinyl, or plastic because it contains no acids or alkalis.
Metal Rescue reps claim their product is easy to use with virtually no labor involved, like no scrubbing, dipping, brushing, or other agitation to remove rust. Using a three-step program, you can de-rust your metal parts by simply soaking, check, rinse/dry. We opted for the easy approach rather than using electrolysis, sand blasting or dangerous naval jelly chemicals. To test this magic in a bottle for ourselves, we rummaged through the garage and gathered up a handful of rusted parts ranging from mild to the more severe.
Although Metal Rescue doesn’t require any prepping prior to soaking, we recommend pre-cleaning your parts to speed up the process of rust removal as well as extend the life of the chemical. We went one step further to ensure a clean finish by scrubbing our parts with a Scotch-Brite pad to remove surface rust.
After more than five minutes of scrubbing one side of the badly rusted Subaru EJ20 oil baffle plate, it was evident the rust had worked its way in and around the metal and wasn’t coming off. We purposely left the other side of the baffle tray untouched without any prep work to put Metal Rescue to work.
We began the process by soaking the parts inside a plastic container. A pair of badly rusted license plate bolts, Craftsman wrench, and harness bar were all thrown into the mix to put Metal Rescue to the test. Metal Rescue reps state that one gallon of Metal Rescue should be able to de-rust approximately a 1⁄2 pound of rust.
Notice: The harness bar’s powdercoated surface is also submerged within the chemical. Fear not, the solution has been designed not to remove or harm the vast majority of paint coatings. However, if there is a layer of rust under the paint or paints (and inks) using iron oxide pigments (usually orange or red) may dissolve the pigment in these types of paints. It is always best to test on a small section or hidden area prior to use. Within an hour of soaking, the rusty harness bar bolt looked as good as new.
Check periodically as soak time ranges according to the severity of the rust and the surface area. Light rust will require 5 to 30 minutes, moderate rust takes up to four hours, and heavily rusted items may take up to 24 hours. If you are trying to speed up the rust removal process, Metal Rescue will work faster up to a temperature of 150 degrees F (70 degrees C). Do not leave your part in the solution after rust is no longer present or the metal might become dark. After soaking the rusted license plate bolts for five hours, you can literally see the rust falling off. Also, notice the oil baffle plate beginning to show its original metal surface with nothing more than soaking in the tub of solution—now that’s amazing!
After a 24-hour soak, the wrench and baffle plate were both removed. Check out the before-and-after photos, including both front and backsides of the baffle plate.
Eastwood Metal Blackener Solution
During the final stages of testing, we used Eastwood’s Metal Blackener Solution on our renewed and rust-free license plate bolts, which were now exhibiting a dull raw metal appearance. The Eastwood blackening solution is a mild acid solution mixture of Selenious acid, phosphoric acid, copper, and nickel that lets you reproduce the OEM look of black oxide on any iron and steel nuts, bolts, and brackets quickly, safely, and economically with no special equipment.
This chemical is odorless, non-caustic, and produces no fumes, making it safe for usage in and around the garage. Keep in mind this is not a paint product; the blackener is an etching solution.
To show how the product works on a larger scale, we dipped the corner of our previously treated Subaru oil baffle plate for a few seconds to show the blackener’s result. Large parts can also be blackened by placing the solution in a large clean container and brushed on heavily using a foam-type paintbrush.
Once the part is clean of any rust and paint, it is then submerged into the solution for anywhere from 20 seconds to a minute (depending on surface area) as the chemical turns the metal from silver to black. After blackening, rinse the part in clean tap water for 10 to 20 seconds, and dry and wipe the surface with a clean cloth. Applying either a clearcoat or Eastwood’s Diamond clear satin will help to maintain a rust-free finish.
This photo illustrates the remnants of residual rust from the two-turbo exhaust housing we tested following our baffle plate that were badly rusted from sitting in storage the past few years. Now that’s a ton of rust!