Lemon juice is the classic homemade rust remover for delicate fabrics, one I remember my grandmother using. It is recommended in household hints books from the Victorian days and household hints sites on the Internet. I seldom have lemons in the house as the same time as I discover that something left a rust stain on a shirt, but I do have the active ingredient: pure citric acid.
Citric acid has all the buzzwords a rust remover should have for home use: it’s biodegradable, it doesn’t give off nasty solvent fumes, and it’s cheap.
Is it safe to use citric acid? Generations of housewives have used it without hurting themselves. Follow the directions on the package. Keep it out of the reach of children. Always add the powder to water, not water to the powder.
Where to find Citric Acid:
Citric acid crystals or powder is a chemical that is sold in bulk for cooking, canning and brewing. Making homemade rust remover is not its main household use.
Citric Acid (sometimes labeled as sour salt) is used in Jewish cooking. It can be found in the kosher food section of many supermarkets. It’s also sold in health food stores as a sprouting aid. Look near the seeds sold for sprouting or the sprout-making equipment. If all else fails, buy it where I do, at the home brewer’s supply shop. Citric acid is used to adjust the pH of beer or wine.
How to Use Citric acid as a Homemade Rust Remover:
I mix a teaspoonful of citric acid powder in a quart of water and it’s instant homemade rust remover. Place the rust-stained fabric on a white towel in the sink and drip the citric acid solution onto the spots. It will chemically react with the rust and carry the rust into the towel.
Finish by rinsing the fabric in water and wash as usual.
When Citric Acid Isn’t Strong Enough, try Oxalic Acid:
Oxalic acid is an organic acid that occurs naturally in spinach and rhubarb. Powdered oxalic acid is sold as a wood bleach in most hardware stores. If you have sturdy fabric, or want a homemade rust remover for porcelain and other hard surfaces, try a teaspoonful of oxalic acid in a quart of water. It also removes “mildew” spots from clothing.
CAUTION: If you spill a strong solution of it on your hardwood floor, it might damage the floor. Wear rubber gloves, and don’t inhale the dust. It’s irritating to your skin and lungs.