National Clothesline
I recently completed a study of different drycleaning systems and the quality they produce.
The drycleaning systems included
those using perc, GreenEarth,
hydrocarbon and K-4. Some of the
systems used distillation and others
did not.
We were interested in
determining the degree of
redeposition of soil and graying.
This is to answer customers’ complaints on fabrics not being white enough after drycleaning or
not matching half of an outfit that was not cleaned.
Testing procedures
We used new white cotton swatches for the testing. We used a light meter to calibrate the
differences in brightness after cleaning.
We used one drycleaner for reference. We wanted to make sure the drycleaning system can
produce a pure white fabric compared to the original without any change. We did not want any
change attributed to fluorescent dye breakdown or other finish.
We attached the fabric to a garment to be cleaned in a light load.
Testing after drycleaning
• We examined the fabric visually for any change compared to the original.
We used a light meter to determine degree of color change.
Fatty acids and oils. We applied a drycleaning solvent to clean a sample and noted any rings.
Redeposition of soil. We applied oily-type paint remover to the sample with ammonia, then
tamped and flushed. We checked for rings and light areas.
Dye redeposition. We applied stripping agents to sample and checked for light areas.
The different drycleaning solvents did not have an impact on the brightness of the fabric
sample. The drycleaners who maintain their equipment and cleaning systems had the best
The drycleaning systems using no distillation had equally good results when the operator
followed proper cleaning practices and maintenance.
Drycleaning detergents did add to the brightness due to the brighteners used in the products.
The detergent did not change the brightness if the fabric grayed due to redeposition.
How to check your cleaning system
1. Cut a white sample cotton fabric in half and attach it to a garment to be cleaned in a light
load. Compare the sample with the original fabric.
2. Check solvent flow. It should not take more than one minute to fill the  wheel when solvent
comes from the tank through the filter into the wheel. This is important because you want quick
solvent changes to discharge soil to the filter.
3. Check filter pressure. When pressure is five pounds above normal manufacturers’
recommendations there is a likelihood of poor cleaning. It may be time to spin the discs or
change the cartridges.
4. Solvent clarity. The solvent should be amber or the color of light beer.
5. Solvent temperature. Many drycleaners heat up the solvent to increase the cleaning power
of the solvent. The heated solvent makes it more aggressive to remove oil, greases and waxes.
It must be noted that the heated solvent removes more dye from fabrics and may use up carbon
cartridges quickly.
6. Make sure the still is operating properly. There should be no boil-over and the solvent
returned to tank should be crystal clear. Make sure there is the proper amount of sludge left
when cleaning out the still.
Drycleaners can maintain any cleaning system if proper maintenance is followed.
I have seen some drycleaning systems with a breach in the filtering system that allows soil to
redeposit onto fabrics. I have also observed stills that were not operating properly causing poor
solvent conditions.
Proper classifications of fabrics and proper prespotting are also important factors.
Solvents, filtration and brightness
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Dan Eisen is the former chief garment analyst for the Neighborh