I know it’s very frustrating when you have cleaned up a spill or a stain and then like an annoying relative it comes back. This is particularly maddening when you have paid a professional carpet cleaner a good bit of money and then the stain comes back.
There are two reasons why stains come back.
The residue is what is left over after an incomplete cleaning attempt. This is usually a sticky alkaline cleaning agent that has been left in the carpet and soil is sticking to it. It would be like washing your hair and only rinsing half of the shampoo. Your hair will get dirty twice as fast. Usually what happens on carpets is the homeowner sprays too much alkaline cleaner on a spot and rubs it out. The spot disappears. The homeowner is happy, mission complete, except that a few days later that dirty spot reappears. Sometimes it could be that an alkaline cleaner has spilled on the carpets. Four-year-old Susie is helping with the laundry and opens the cap and spills two cups of laundry soap on the carpets. There is going to be so much soap in the carpet that you are going to need some expert advice. Or, it has been known to happen that an inexperienced carpet cleaner has left residue in the carpets.
Whatever caused the problems, here are the solutions.
The small residue spot:
When you are cleaning up a stain, rule number one is to use the proper cleaning solution. Using the wrong solution can at best be ineffective and at worst damage your carpet. On our website is a page with the best cleaning solutions for different kinds of stains.
When you use an alkaline stain remover, you need to either rinse extremely well or rinse and neutralize the area with an acidic solution to remove any residue. White vinegar in ½ cup to a quart of warm water mixture is a good acidic cleaning solution that will remove the residue. Pour some of the vinegar solutions on the spot and blot dry.Use the vinegar after you have rinsed out the spot thoroughly.
The large volume soap spill:
If you have spilled a large volume of an alkaline cleaning solution then you are going to need to get a little more aggressive.
Rent a portable steam cleaner. Make sure it has a hose attachment for cleaning upholstery. Using two cups of white vinegar to a gallon of warm water fill up the tank of the carpet cleaning machine. Spray down the “soapy” area and then extract with the machine. Do this over and over and over until there is no more “soap” coming out of the carpet. Be aware that because the soap foams up your machine will fill with foam quickly. If you suck up a little bit of straight vinegar every few times you extract, this will help to keep the foam down.
The carpet cleaner left residue:
If a carpet cleaner leaves residue in your carpets then call them up and ask them to come and fix the problem. If not then you will either need to call a better professional or if you clean yourself then you can follow the same procedure shown above except you will be cleaning a bigger area. Use the vinegar or better yet purchase an acidic neutralizing solution from your local carpet cleaning supply store. Clean the carpets just as you would as if you had put an alkaline solution in the machine. You may have to go slow and be very thorough.
The other and much more common cause of spots reappearing is called wicking. If a spill or stain goes down deep into the fibers and particularly if it goes through the backing to the padding under the carpet it is going to be really hard to clean that spot out. What you see as the stain on the top of the carpet is kind of like the tip of the iceberg. You can clean up that part visible on the surface but a part of the remaining hidden stain wicks up to take its place. This does not happen immediately, it takes hours or even days. The stain needs to be moist to do this, which why certain types of stains like oil stains will come back easily. One of the biggest headaches for professional carpet cleaners is when after deep cleaning a carpet, a stain that was in the backing and we did not even know was present wicks up to the surface after we leave. Any stain that is bigger than about the size of a hand is one that could sink down to the backing and wick back up later.
The answers to wicking:
If you are cleaning a larger spill after you have gone through the cleaning process and while the spot is still damp, take a white cotton rag folded several times and place over the stain. Place a piece of plastic of the cloth and then stack several heavy hardcover books on this. The stain will wick up through the carpet fibers and into the white cloth. Then re-clean the remaining spot on the carpet surface. With large spots, you may have to do this several times.
Large volume spills:
Certain types of large volume spills or stains might require that you pull up the carpet and remove the padding. The padding is just a big sponge and without special professional carpet cleaning tools, you will not be able to remove stains from the padding through the carpet. The easiest thing to do is to simply cut out the stained padding and replace it with new. If there is a stain also on the sub flooring you will need to clean that and then paint the floor with sealer paint.
The Water Claw:
A professional carpet cleaner may have a tool called a Water Claw which is a tool that allows cleaners using van mount steam cleaning systems to extract many types of stains from the padding right through the carpets.
A process that is helpful with wicking is called encapsulation. Encapsulation products create minute crystals that absorb the stain when it begins to wick up top the surface. These crystals dry to a fine invisible powder that you vacuum up during your next regular vacuuming.