Our 4 x 6–inch test samples were uniformly pre-rusted in a seawater-exposure rack by NASA's Corrosion Technology Laboratory at the Kennedy Space Center. Each steel sample has a piece of C-channel welded to it, which allowed us to test the rust removers on a flat surface, an inside and outside corner, and a weld.
Price: $23 for 1 gallon
Effective and quick. After six hours of soaking, the test blank was quite clean. After 12 hours, it was spotless, including the corners and the weld. We noticed some carbon deposits had leached out of the steel, but with a little effort we managed to wipe these off.
Price: $11 for 16 ounces
Its thick, honey-like consistency provides good vertical cling and required very little scrubbing to remove rust. The Bull Frog stayed moist and effective, even after being exposed to air for two hours. It was also the only product we tested that prevented flash rusting (which can happen within 20 minutes of treatment if you don't prime or seal quickly) by using a Vapor Corrosion Inhibitor that bonds electrochemically with the freshly cleaned surface.
Price: $25 for 1 gallon
Six hours in the Metal Rescue bath will get your part clean enough to finish the job with hand tools. Leave it in for 24 hours, though, and it's impeccable. Worth the wait.
Price: $20 for 16 ounces
Dissolve a lot or a little of this crystallized product in water, depending on the job. Brush-on application was moderately effective, and soaking produced better results if you waited a full day. Unlike other options, you can apply this with a garden sprayer to vertical concrete or plastic that's been stained by irrigation water.
This story appears in the December 2015 / January 2016 issue of Seniorhelpline.