Laundering usually works best for stains that are relatively fresh. Once the rust has penetrated the material and had time to sit, simple soap and water may not do the trick. If you pull your clothes out of the machine and the stains are still visible, it’s time to try something else. You may need to bring on the heavy-duty chemical stain removers at some point, but a lot of blemishes will come out with milder methods, provided you have the time and patience to try them.
Lemon Juice Treatment
From a chemical perspective, rust happens when the iron particles in metal come into contact with oxygen, creating iron oxides that have a characteristic red-brown color. One of the best ways to break down these compounds is to apply a mild acid; most acids digest or dissolve metallic compounds, which in the case of rust stains means that the stain can actually be “eaten” or lifted out of the fabric, almost from the inside out. Lemon juice is an ideal acid for this purpose that most people have or can get relatively easily, and it is concentrated enough to get good results in many cases. Distilled white vinegar can also make a good substitute.
Simply saturating the garment in the juice or vinegar will sometimes work, though you’re likely to get better results by first mixing the liquid with a bit of table salt to form something of a paste. The salt helps the acid bind to the stain and holds it in place, allowing it to do its work on the metal particles. How long to let things sit depends in part on the severity of the stain and the delicacy of the fabric you’re working with, but you’ll likely need at least fifteen minutes and up to an hour or more.
When it looks like the stain is breaking free, blot the area with cool water and gently wash the salt mixture off. You’ll want to be careful not to scrub the mixture into the fabric since this can make things worse; setting the garment under running water or using a clean wet cloth to slowly pat away the paste is usually best.
Harnessing the Sunlight
Natural sunlight also has bleaching and sanitizing properties that can be a good compliment to lemon juice treatment. Once you’ve gotten as much of the rust out as you can, try setting the fabric in a sunny window or on a clothes line to let the sun’s UV rays penetrate the material. Many people find that any remaining rust simply flakes off once the clothes are dry.
Another “green,” or non-chemical, option is to soak your stained clothes in a broth made from boiled rhubarb. This method tends to be most popular on clothes that have extensive stains, or stains over large areas that would be burdensome to address individually. The basic idea here is to boil several stalks of rhubarb in a large pot of water for about half an hour. Rhubarb, like lemon, is high in natural acid, though the acid compounds are stored in its stalks and tend to activate when cooked.
Take the stalks out of the pot once half an hour is up and turn the heat off, then wait for the water to cool slightly; you’re looking for about room temperature. Put the stained clothes in and allow them to soak until the stains are removed, or are at least loose enough to remove with a soft cloth or brush. Exactly how long you need to let things soak usually depends on the clothes, but you should be careful not to leave things for too long, particularly if your broth is on the stronger side. Rhubarb juice is sometimes used to dye clothes, and the last thing you want is a shirt that is stain free but in a different color. Most experts recommend soaking for no more than an hour, though closer to 15 minutes is usually enough.
Cream of Tartar
If you have cream of tartar in your spice cabinet, mixing it with a bit of hydrogen peroxide might also help. Cream of tartar, which is known chemically as potassium hydrogen tartarate, is a binding agent that can help lift rust out of most types of fabric and upholstery, and can sometimes even take rust off of metal pieces like furniture or appliances. Dab the mixture onto the stain with a cotton ball or soft cloth, then allow it to sit for about an hour before rinsing with cold water and laundering as usual.
Phosphoric Acid and Commercial Rust Removers
If none of these home remedies work, or if you’d prefer to use something a bit stronger, your best bet may be to look for a commercial rust removing solution. One of the most popular choices is a phosphoric acid compound that can be rubbed into the stain; it often comes as a gel or thick liquid, and is frequently sold under the name “Naval Jelly.” It is often marketed for more industrial purposes like taking rust off of machinery, but many people find that it is also quite effective for clothing. You just have to be careful not to leave it on too long; in most cases it’s best to gently rub the gel into the stain, then wash it right away to prevent any discoloration.
All-purpose laundry stain removers may also do the trick, but it’s important to carefully read the manufacturers’ instructions before treating your fabric. Anything that contains bleach, for instance, should not be used on rust stains since bleach compounds can sometimes make them permanent.
If nothing seems to be working, your best bet may be to take your stained clothes to a dry cleaner. In most cases it’s better to give up after a few tries rather than risk setting the stain, and professionals usually have more advanced tools that can do a better job on really stubborn marks. It’s really important to point out the stains when you drop things off, though; if the dry cleaner doesn’t notice and cleans your clothes normally, there’s a chance the rust marks could get worse.
A Word of Caution on Heat and Dryers
With the exception of leaving stained clothes in the sun to dry, you should be really cautious about exposing your garments to heat. Only put things in the dryer if you’re really certain that all of the rust has come out since heat often “sets” stains, making them even harder if not impossible to remove.