Insoluble versus soluble soils
Insoluble soils are those you have to pick up to remove such as sand, dirt, dust, paper clips, staples and so forth. Vacuuming is the most common and preferred method for lifting insoluble soils. The most insoluble soils are common dirt and dust, because when these substances mix with water (as happens with a wet cleaning), they form mud. As you might guess, it’s much easier to move dry soils out of fibers than mud. For this reason, a thorough vacuuming – with a good vacuum – should precede any wet carpet cleaning. In the ideal world, we’d vacuum carpets at least every other day. It’s the best method to prevent accumulation of insoluble soils.
Soluble soils dissolve in water, detergent or solvents. Examples of water soluble soils include: beverages, syrup, ice melting salts, etc. Examples of solvent soluble soils include: cooking oil, paint, tar, chewing gum, and crayons. Most cleaning products remove soluble soils by dissolving them with a solvent. Even water is a good solvent.
Spots vs. Stains
People often use the terms “spots” and “stains” interchangeably, but they have an important distinction between them. A spot is a visible discoloration on a surface resulting from a soil that you CAN remove. A stain on the other hand is a visible discoloration on a surface resulting from a color that permanently attaches that you CANNOT remove. They “stay in.”
Skillful cleaners can sometimes turn what appears to be a stain into a spot, however, poor cleaning techniques can also change a spot into a stain. This is why getting the right spot cleaning knowledge, education and products is crucial to carpet cleaning success.