How to Remove Dried/Old Mustard Stains From Carpet
Mustard stains can be one of the most stubborn types of stains, even professional carpet cleaners think they are a huge pain. There is only one color safe method that I know of that will safely remove mustard stains, and I'm going to teach it to you on this page.
Mustard gets it's yellow color from the turmeric spice, which gets it's color from a molecule called curcumin. Curcumin molecules have strong dye like properties so they easily become fixed to carpet fibers resulting in permanent stains. Unfortunately, there is no spotter that can easily remove mustard stains from carpet, so we have to use an oxidizer to make these yellow stains invisible. The method that I am going to show you is a color safe method, so you can safely use it on colored carpets without damaging them. So how do you remove a an old/dried mustard stain? You use hydrogen peroxide and UV light (artificial or sunlight)! These two ingredients result in a chemical reaction called an advanced oxidation process, and it will make even the brightest mustard stains become invisible.
But before we apply the hydrogen peroxide and UV light, lets try to remove as much of the mustard as possible with a spot removal process.
You will need: 3% hydrogen peroxide, and a waterproof UV light (or direct sunlight).
STEP 1 of 2 - Spot Removal with 70% Isopropyl Alcohol
It is important to remove as much of the mustard as possible with a traditional spot removal process. I am assuming that most people have already tried some kind of spot removal process, and were still left with a yellow stain. If this is you, you can skip step 1, and jump to step 2.
Dampen the stained area with 70% Isopropyl Alcohol.
Using a white towel, blot the stain. You can also gently wipe the spot from the edge of the stain to the center being careful not to spread the stain.
Place a clean cloth over the affected area and apply pressure to absorb any remaining alcohol from the carpet.
STEP 2 of 2 - Remove Remaining Yellow Stain
Step 1 will make the mustard stain lighter, but the stain likely won't disappear with spot removal alone. This is because the yellow curcumin molecules that give mustard its color have become fixed to the carpet fibers. In step 2, we are going to make this yellow stain invisible using hydrogen peroxide and UV light (or sunlight). This method is safe to use on colored carpets, but I always recommend testing the hydrogen peroxide and UV light together in an inconspicuous area on your carpet prior to using it in an openly visible area. All carpets and environments are unique, so it is always a good idea to test cleaning products and methods to be sure they don't cause damage.
Dampen the stained area with 3% hydrogen peroxide.
Leave UV light over the stained area for 15 minutes. Note that this process is safe to use on all synthetic carpets.
After 15 minutes the yellow color has mostly disappeared. Repeat step 6 and 7 until all of the yellow stain has been removed.
You can see the difference between photo 2 and photo 5. After 15 minutes of oxidation the curcumin molecules are losing their color.
Use a white cloth to absorb any excess hydrogen peroxide solution from the carpet.
Cover the stained area with a 395nm waterproof UV light. See below for product recommendations.
Brush the tufts to form a valley, exposing any staining at the base of the carpet tufts. Then place the UV light over the stained area.
Allow carpet to dry. Any remaining hydrogen peroxide will decompose into oxygen and water. the water will evaporate leaving zero residue behind.