ICS Magazine

Basic Spotting Principles

April 11, 2006


As most conscientious cleaning technicians have learned, when you make a complicated task a procedure, it ceases to be a problem. Without a procedure, it may always be a problem. There are six basic spotting procedures, one of which is absolutely guaranteed to remove any spot or stain known to man!

Remove the Excess

K.I.S.S. - Keep It Simple Stupid - should be your guide here. By "remove the excess" we're referring to a process whereby crusty, powdery or any other forms of solid substances are physically (not chemically) broken loose from the fiber surface and extracted through dry vacuuming. This is accomplished with a spatula or spotting brush, followed by extraction with an appropriate canister-style vacuum. Excess wax, dry pigment, particles of carbon, starchy substances - even dry, sugar-based food stuffs and crusty residues - respond particularly well to vacuuming after breaking them up with gentle agitation. In fact, some agents - particularly carbon or pigment - aren't removed dry, they will be suspended and carried by your "wet" chemicals to the fiber's surface, where they'll bond like a dye. That's when spotting gets really tough!

In the common-sense department, if a quantity of highly viscous spot contaminant like grease or ketchup is lying on the fabric's surface, scoop up the majority of the contaminant with a spoon or bone spatula before applying chemical spotters.

Finally, if a quantity of liquid such as oil is spilled on a fabric, rather than pouring on quantities of chemical spotter, you should sprinkle an adsorbent or absorbent on the contamination before chemical application takes place. There are a variety of products sold commercially; however, diatomaceous earth (white swimming pool filter powder) will do a good job of absorbing excess liquids.

Dissolve

A solvent is a substance that dissolves another substance. By "solvent action" we mean that we are going to dissolve one substance (the spot) with another (the spotter).

Solvent action occurs in two distinct categories:

Dry solvent action. Dry solvents are liquids that contain no water. They are used on oil-based (particularly petroleum-derived) spots. Dry-solvent action involves dissolving oils, greases, gums, resins, glues, tars, etc. with a dry cleaning solvent. There are many classes of dry-solvent spotters, such as aliphatic hydrocarbons (odorless spirits or "OMS"), chlorinated solvents (trichloroethylene, 1, 1, 1- trichloroethane, perchlororethylene), glycols (ethylene or propylene glycol monobutylether - Butyl Cellosolve, Solvent EB), alcohols (ethyl, methyl, isopropyl), ketones (acetone, amyl acetate), etc.

Fortunately, formulation chemists decide what does the best job on which spots; you just apply the appropriate spotter and enjoy the benefits.

Wet solvent action. Water is the universal solvent. It dissolves more substances on this earth than anything else. Until now, you've probably used the term "solvent" to indicate only dry-cleaning agents. However, by definition, water is also correctly termed a solvent, since it readily dissolves many substances. Therefore, wet-solvent action involves dissolving sugars, starches, salts, some dyes, etc. with water. Of course, water works best in this capacity when a detergent is added.

Lubricate and Suspend

This addresses the third category of containment - insoluble particles. Particle contaminants, such as clay, dye pigment, carbon and metal ores can't be dissolved with normal spotting agents. They, along with the fibers to which they are attached, must be lubricated with a detergent or dry-solvent "film" so that insoluble (un-dissolvable) particle soils can be suspended until absorbed by blotting or extracted through vacuuming.

Read this carefully: although lubrication and suspension is an entirely different removal method than solvent action, both normally occur at the same time. Only the types of contaminants affected are different. This is nothing for you to worry about, just understand what's happening. As with solvent action, lubrication and suspension occurs on the dry-solvent side of the spotting spectrum as well as the wet, with end result being that suspended insoluble particles are ready to be removed.

If I still have your attention, here's another important point: it's critical to use the proper application procedure and techniques when removing discoloring particle contaminants. Water by itself, especially hot water, tends to suspend fine particles (e.g. carbon, pigment) and transport them to the fiber dye sites, where they can be bound by chemical forces to create a potentially permanent stain. So after dry vacuuming as much particle contaminant from fabrics as possible, follow up with concentrated detergent spotters and aggressive agitation to suspend that which remains, then flush carefully with hot water chop-stroking to remove suspended pigments.

The bottom line is, don't create problems for yourself by starting with chemicals before dry vacuuming first. Dry vacuum, then lubrication and suspension. Got it?

Digest

This approach involves persistent protein spots, such as egg, blood, urine and milk, and the application of living organisms called enzyme digesters (literally, spot eaters).

Proteins are complex long-chain amino acids. When treated quickly, many protein contaminants (e.g. blood) can be rinsed from fabrics with plain cold water. However, with time, or due to exposure to other environmental influences like heat or sunlight, protein may become an insoluble substance that cannot be readily dissolved by water-based cleaning agents until it is substantially changed or acted upon by enzyme digesters.

The process is similar to what happens in your stomach. The nutrients in the steak you just ate (or will, once you become an educated professional and can afford it!) cannot be dissolved into your water-based bloodstream until the meat protein can be changed into a useable (soluble) form. The job of the enzymes in your stomach is to change meat protein from an insoluble substance into a soluble one, when it can then by carried away by the bloodstream. This is digestion.

Chemical Change

This method involves using various reducing or oxidizing agents that essentially change dyes into colorless compounds - or remove them with solvency and suspension - without removing color from the fabric. Most of these color-removing agents are a real mystery to the average technician, but they need not be. With a little education, they can become powerful allies.

Reducers remove oxygen from dyes to render them colorless, while oxidizing agents literally add oxygen to change the dye molecule so that it no longer can reflect color. Reduction reactions may not be permanent, as dye can regain oxygen from rinse water or the air; oxidizing reactions, on the other hand, are permanent.

Carpet offers limited options in the "chemical change" category. The fibers that withstand aggressive bleaching - olefin, polyester, acrylic - don't stain, and the ones that stain easily - nylon, wool, rayon - can't withstand aggressive bleaching techniques without wholesale color loss. However, a lot of upholstery responds well to chemical change or "bleaching" agents, due to specific fiber types and dye techniques.

Sectioning

Last but not least, here is the final method of spot removal for use on carpet, the one guaranteed to remove any spot or stain. It's called cut and plug or, if you've been properly educated, "sectioning" the carpet.

Now, before you throw the magazine down and impress those nearest you with your repertoire of four-letter words, think: we carpet cleaners have an advantage over dry cleaners in that we actually do have a sure-fire method of removing even the most stubborn stains. Every professional spotter should have the knowledge and equipment to employ this carpet repair/spot removal technique. The fact is, there are certain carpet stains - think burns and discolorations - that simply cannot be removed without following this highly practical course of action.

Now, if only it was that simple with upholstery fabric! Since most upholstery is constructed in the form of a flat weave (warp and weft yarns, but no pile yarn), sectioning is usually not a viable option.

Another entry in this category of "spot correction" techniques is re-dyeing a discolored or color-loss spot. With today's technology and instruction, many color-loss spots can be repaired through the re-application of dye. Fibers that may be spot-dyed include most cellulosic and protein fiber, along with rayon and nylon.

Unfortunately, if the fiber has been discolored with strong bleaching agents, the fiber's dye sites may be damaged to the extent that the fiber will no longer accept the level of dye necessary to repair the discoloration. At this point, sectioning may be the only satisfactory alternative.