Rust stains can sometimes be removed from concrete by scrubbing with a solution of four ounces of oxalic acid in a quart of water. Oxalic acid is sold in crystal or powder form at paint stores.

A: Oxalic acid is a potent but toxic cleaner that removes rust and stains caused by iron, water and tannic acid. It's available in dry crystal form, to be dissolved in warm water for use.

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After this victory, I went to the garage to see if the oxalic acid would remove harsh rust stains left on the concrete floor from the bottom of my snowblower.

Choose an out-of-the-way spot in case the acid does damage the sheen. What about using oxalic acid outdoors to clean rust from vinyl siding, brick, mortar, concrete and so forth?

Ever had a beloved pocket knife or saw go rusty? We have. Thankfully, when you learn how to clean rust off tools the right way, a patina of red-orange rust doesn’t mean the end of your tool’s life.

A: Rust stains on concrete seem to respond best to acids of various types. The classic treatment is oxalic acid, which is sold at some paint stores for use as a wood bleach.

According to Future Market Insights, the oxalic acid market is projected to grow from USD 1 billion in 2025 to USD 1.7 ...

Rust remover. I don’t possess the patience for 10 days of poulticing the patio, so I turned to Iron Out, a plant-safe liquid containing oxalic acid.

Things to Do Oxalic acid is the solution for removing rust Click to email a link to a friend (Opens in new window) ...

Make a solution of oxalic acid crystals (available in paint stores) to saturation in hot water in a plastic bucket; never use metal with oxalic acid. Apply it to the stains with a paintbrush.

I would start with oxalic acid. This product comes in crystals and is readily available online. Mix it according to the package instructions and pay close attention to all the warnings on the label.