Ecoxall Oxalic Acid Fine Powder, 99% Pure, 10.1 lbs (160 oz), Pack of 1

This cleaned that toilet in 20 minutes, I didn't have much time left as I was getting off work, so I had to rush in see just how well this,was going to work? And it cleaned so well , in such a short amount of time added in warm water to the mixture and made a paste and blotted it on to the stain.

Great product. Removed all water rust stains on the house from the sprinkler system. Used 1 cup in a gallon of water. Used a paint roller to apply. Let it sit for 15 minutes, scrubbed just a little bit on spots that still had rust. Then rinsed with clean water and all rust was gone.

Just had a new Denya counter with an oil finish put in 6 months ago. Had some metal canisters on the counter and a metal cup. Water was spilled on the counter and seeped under the canisters and cup. The metal reacted with the water staining the wood. I tried some home remedies first and nothing worked. I was terrified I'd have to call the installer to come out and sand it out. With nothing to lose, I decided to try the oxalic acid. Only giving 4 stars because it comes with no directions, usage guides, or precaution literature. It's an acid, it should come with some warnings. Anyway, I found some easy how-tos on youtube. It worked crazy good. Just applied a little of the solution, let it sit a minute, then rinsed. The counters look great! I did lightly sand some of the areas to see if that made a difference, it didn't seem to. But all the youtube videos say you should sand if there's a coating on the wood of any sort. As a side note, I poured the leftover into an old bathtub that had rust marks and it took those off too.

Worked amazingly well!

Decent price. Arrived timely. Did what it's supposed to.

Cleaned the stains off my boat like nothing else

Having a bunch of fun using this to remove rust from old tools. The quality seems normal. By which I mean I don’t have an analysis protocol to say for sure how perfectly it is what it says, but it looks & behaves differently from malic & citric acid. The crystals seem to be uniformly sized, a bit smaller than kosher salt flakes. When I forget to wear gloves, the back side of my fingernails stains brown and I have indifferent luck scraping it clean. (the nail extending from the end, not the nail bed. I suspect it’s reacting to something on the nail even tho I use a nail brush at least daily.) If you want to de-rust iron, this is one workable option.

This did a great job lightening up the wood for refinishing furniture. The color came out even so I was able to stain rather than paint.