What happens that causes a spot to be chemically set? I found myself telling a customer that Monday after they threw the whole cupboard at a dog poop stain. And **** i dont even know what exactly happens chemically to a spot to make it set.
In my understanding of it a stain is the absorption of a colour pigment into or permanently bonding to a fiber. If it's not absorbed and not permanent then it is dirt that can be removed. clear as mud AY.
Cleaning is all about breaking bonds. If you know any chemistry, you understand that there are different kinds of bonds. Same with stains. Dye bonds differently than rust, and different still from mud, and so forth. When you can identify what caused a stain, you have a better chance to break the bond and remove it. When you can't identify what caused a stain, a progressive spotting effort is prescribed, beginning with inexpensive and easy, heading toward dye removal (heat accelerated, etc) and so forth.
A number of things may happen. As posted above, there can be chemical bonds between the fiber and the staining material. These bonds are what hold dyes to the fiber. Chemical reactions from some cleaning products may alter or change the conditions forming a bond that was not previously there. Now the stain is not just on the fiber but has become part of the fiber. Most cleaning agents include surfactants. One purpose of a surfactant is to lower the surface tension of liquid cleaning agents so that they penetrate deeper into a fiber. This can allow your cleaning solution to reach stains deep in the fiber. But when mis-used, surfactants can carry a stain deeper into the fiber making it very difficult to reach.
