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The Real-World Science of Spotting

I’m amazed at the reaction of some “cleaners” when they first realize that stain removal is as much an art as it is a science. But one must have the science mastered before crossing over to the “artist” side of the profession.
Applying the science of spotting is an act that requires one to think about the task, and most of the typical drycleaner’s time is spent concentrating on a particular stain. This month, we’ll explore considerations that can affect our course of action in removing a stain, such as fiber, fabric construction and trims.
A fiber is what makes up the thread. Multiple threads are woven or otherwise constructed into panels of fabric. Fabric is cut and sewn into a garment or part of a garment. Designers and manufacturers may add decorative trims to enhance garments’ marketability. Rest assured that marketability and profitability rank high among the producer’s concerns, and that serviceability is not as high a priority.
The origin of the fiber used to make the thread determines how aggressive one can be when attempting stain removal. Fibers that come from plant cellulose include cotton, linen and ramie — naturally stiff but softened artificially to make it feel like linen.
Cellulose fibers are sensitive to acids. This means that in real-world applications, one needs to work quickly when using tannin formulas on cotton, linen and ramie. Never leave a tannin spotter on a piece of cellulose and walk away, unless you wish to invite a claim.
Fibers that come from animals are protein fibers; these include wool, cashmere, angora and silk. All protein fibers are sensitive to alkalis, so in the real world, you need to work quickly when using protein formulas on protein fibers. Never leave a protein spotter on a piece of protein-based fabric and walk away.
In addition to its vulnerability to protein formulas, silk is affected by salt, alcohol and light, and weakens when exposed to water. Be careful when applying mechanical action to a silk fiber after using the steam gun; this will often “knock out” the color.
What’s actually going on is that the silk threads are weakened by water, causing the area to reflect light differently than the surrounding areas. Under a magnifying glass, the area will look fuzzy, with the silk fibers going in all directions. Also remember that the only bleach that should be used on protein fabrics is diluted hydrogen peroxide.THE SYNTHETICS
Modern chemistry has given us a large group of synthetic fibers, most of them produced from petroleum. Petroleum fibers include Spandex, nylon, acrylic and polyester. All are sensitive to heat — acrylic the most sensitive.
In real-world applications, the heat and pressure of steam in spotting can soften fibers to the extent that garments are permanently stretched and damaged. The use of petroleum-based spotters can lead to permanent discoloration if they penetrate the petroleum fibers and bond with them.
Metallic threads come in two types. The more durable type bonds the metallic to an inner thread, in most cases cellulose. A circular or nearly circular shape characterizes this variety. The second, more fragile metallic thread is simply a metallic material cut into lengths. This metallic material is interwoven with the base fabric.
Never use rust removers on or near metallic fibers, since they will damage the metallic permanently. In real-world applications, you should move the steam gun farther from a metallic fabric to give yourself a cushion of safety.
There is one man-made fabric, rayon, which is a cellulose fiber. Made of wood pulp, it has a well-deserved reputation for problems. It doesn’t hold dyes well and prone to dimensional instability — it often tends to bleed or shrink, or bleed and shrink.
Rayon is usually heavily sized by the manufacturer to give it an appealing look and feel in the store. But these characteristics are only temporary, and can present problems in stain removal. In real-world applications, there can be excessive dye removal in the area of spotting.
The area around the spotted area can form circles as excess sizing migrates to the border between wet and dry. You may need to feather the edges of the circle repeatedly to make it blend with the rest of the garment.
Trims only present an additional set of concerns when it comes to stain removal. A distinctive design on the surface with little or no design on the backside is likely a “stamp” print, for example. In real-world applications, though, using a paint, oil and grease remover (POG) is quite risky.
“The apple on the skirt didn’t look half-eaten when she brought the garment in.” This kind of fabric is easy to recognize and easy to damage. Using glues instead of paint, manufacturers create what looks like a raised-velvet or “flocked” shape. The glue holds the fibers, and areas without glue remain undecorated.
Again, the surface offers a distinctive, striking pattern, while the backside gives little or no appearance of a design. In a real-world application, anything that softens or removes glue will damage the design.
Manufacturers can do the same thing with larger areas of glue and glitter, known as “crushed ice.” Mechanical action in cleaning can even disturb and ruin these surface patterns, and this makes spotting crushed ice almost impossible.
Manufacturers also often use glue to attach eye-catching sequins to formals and casual wear. In the real world, the heat and pressure of spotting can soften glues and cause sequins to be loosened or removed.
You, however, are schooled in the science of spotting, fibers and fabrics, and can learn to recognize these potential problems before they become claims.
 

Have a question or comment? E-mail our editor Dave Davis at [email protected].