An easy way to know if a chem is "residue free" is mix it accordingly in a glass container... let it evaporate... what is left behind???
Field tests won't tell you if the residue is harmful or beneficial. For example, carpet protetor leave a resideu but that is a beneficial residue. Putting products in a dish does account for the variations in how something rinses off carpet compared to how it rinses off glass or other hard surface. It also doesn't account for the present of soils. For example detergents are made to emulsify oils and other soil. If there is no soil present, some detrgents remain sticky. But they change when they combine with soil. So the results of drying a product in a clean dish are very different from using a product on dirty carpet. Here is what we do in the lab. We start with small squares, about 2" x 2" of white greige goods or perhaps another style of carpet. Mix the product being tested and apply it to the carpet sample. Often we want to compare different products, so we may apply different products to different squares. Mark the back with Magic marker to be sure you know which one is which. Take the treated squares along with one or more untreated samples as a control. The carpet squares are placed in a wide mouth gallon sized plastic container along with some official DuPont soil that represents a blend of soils from around the country plus 1 to 2% cooking oils that are found in most homes. Then we add some large ball bearings to simulate the impact of foot traffic pushing soil into the carpet. Put the lid on and place the container in a cement mixer for 30 minutes. This equals about 2 months of traffic in an average home. Remove the carpet samples. Photogrpah them. Vacuum each on for a predetermined time, usually 2 seconds. Photgraph again. Then compare the results of the samples pieces and keep the photos for future reference. You will see what attracts and what repels soil when compared to the control piece or when compared to other similar cleaning agents. Scott Warrington
clean it, wait 24 hours then LICK it...if it tastes like soap or chemical there may be a residue :bigsmiley:
