Shining light on a grey area

Greying is a drycleaning fault that experienced cleaners will be familiar with. However, in our experience, what is not well understood is the complex nature of greying and the various cleaning practices that can cause it or can be a contributory factor. Greying is defined as the redeposition of particulate soiling released during drycleaning, but it also encompasses any overall discolouration resulting from, say, inadequate distillation or dye bleeds. Greying is not normally a problem associated with wetcleaning, but it remains a possibility in the event of inadequate detergency.

Redeposition or discolouration often occurs due to the presence of moisture or lack of detergent and is a cleaning fault mainly confined to white items and pale colours. Unfortunately, it can be difficult and, in some cases, impossible to remove. Small amounts of redeposition are inevitable; it is also accumulative and even in the best process structures it can become noticeable after repeated drycleaning.

What causes greying?

The table, right, outlines the most important issues that expose the cleaner to a significant risk of greying.

Classification

Without doubt classification is the most important factor involved in greying. Bear in mind that greying is cumulative and therefore good classification is critical in respect of ‘whites’ and pastel colours. The mixing of white and pastel colours should be avoided. Including white/pastel items in medium and in dark loads exposes them to a very high risk of greying!

The most problematic aspect of classification arises from colour contrast garments or black/medium items with white or pastel trims, where ideal classification is impossible. However, the rule is the cleaner should always classify to the lightest colour. Unfortunately, there are no easy answers to this dilemma but seriously underloading will go a long way to reducing soil concentrations in the solvent and consequently the risk. In the case of designer garments and very high value items, the safest option may be to clean them on their own.

Excessive regain

Soil that has been released from items during drycleaning and is dispersed in the solvent, is often attracted to any undissolved moisture in the system and to textiles that may be slightly damp or at well above their normal regain. This may well happen during wet or rainy weather and leads to particulate soil being redeposited on the damp garment, causing overall greying.

Cotton textiles are well known for their capacity to absorb moisture and are particularly susceptible to this type of redeposition. The risk is massively increased by poor classification due to higher soil concentrations.

Machine maintenance

Failure to maintain the separator or the button trap in a clean condition can lead to greying. Dirt and impurities, collecting at the solvent/water interface in the separator, can contaminate the distilled solvent. Always clean the separator after a still ‘black-over’, as it will almost certainly be contaminated with detergent.

In the case of the button trap, a blockage may lead to a large volume of solvent being retained in the cage prior to extraction. This often results in massive turbulence, which scours any dirt that has accumulated between the inner and outer cages and which is then distributed all through the load. This can cause serious redeposition and/or cage marks on susceptible items.

In addition to the above, it will be apparent that close attention to the operation of the machine is vital to ensure that malfunctions are detected at an early stage. For example, slightly cloudy solvent may indicate a perforation in the still condenser or a damaged filter.

Free water

Free water in drycleaning is a serious issue as it is frequently responsible for greying and shrinkage. Serious contamination of the solvent is often introduced through machine faults which can be sudden and unexpected. On a day-to-day basis, it is the use of general pre-spotting soap/water mixtures that present the greatest risk. Relatively small amounts of moisture in a drycleaning system are desirable, as moisture can be very beneficial in terms of removing waterbased stains. This moisture is normally held in solution within the solvent by the detergent. However, if excessive moisture is introduced through uncontrolled use of soap/water mixtures or damp garments, the excess moisture may be precipitated as minute free droplets giving the solvent a cloudy appearance and placing susceptible items at increased risk from greying.

When free water is present, cotton and cellulosic items are particularly at risk of greying as the water picks up particulates from the solvent and is then attracted to the fabric. It will be seen that detergent is not only important to assist in soil removal, but it also has a critical role to play in terms of safely controlling moisture and minimising the risks of greying and shrinkage.

Kit spotters

Water based kit spotters present a risk of localised greying, particularly on whites, if they are not flushed out and the fabric fully dried on the spotting table before drycleaning.

This happens when particulates released in cleaning are attracted to the moisture in the spotted area, if drying is incomplete or the kit product has not been flushed out.

Some cleaners flush out stains with the steam gun or the high-pressure water spray; while this is quite acceptable on many garments, on whites and pastels there is a potential risk of localised greying and in the case of animal hair fibres, felting shrinkage.

• If you have problems you would like the authors to examine please send with a good quality, high resolution (300dpi/1MB at least) pic of the item to kathy.bowry@laundryandcleannnews.com

Main causes of redeposition in drycleaning

a. Poor classification

b. Specific items with excessive regain moisture

c. Inadequate machine maintenance

d. Free water in the solvent

e. Excessive use of soap/water mixtures

f. Inappropriate use of water-based kit spotters

g. Steam gunning stains prior to drycleaning

Pale pink angora jumper

Care label: ‘Handwash do not dryclean’.

Problem: This was cleaned in Green Earth and came out heavily greyed and felted. Angora is an animal hair fibre and without exception is the most sensitive of all fibres to moisture in drycleaning. In our view, this garment was carrying excessive regain moisture before cleaning. Mechanical action and excessive moisture caused the felting and attracted particulate soil from the solvent to the garment.

Rectification: Unfortunately, not Possible

Responsibility: If drycleaners/ wetcleaners choose to disregard clear and concise aftercare instructions, it is generally held to be the cleaner’s responsibility, should the garment fail to respond satisfactorily and deteriorate in this way

A dirty water separator can contaminate the distilled solvent

Carry over from this dirty water separator caused overall greying of these cotton curtains after drycleaning. The tie back was not cleaned and looks visibly paler.

Rectification: reclean in clean solvent, but there is little chance of success. Alternatively, you could wetclean.

WetClean: this will give a much better chance of removing the greying, but with a high risk of shrinkage/distortion. Measure first and then try to recover any loss in length by finishing under tension.

Localised greying spoils cotton coat

This cotton coat was pre-spotted with a kit protein remover, before it was drycleaned.

Problem: when it was removed from the machine, a grey patch had appeared where the original stain had been pre-treated.

Cause: the protein remover was not flushed out and the area not dried off before cleaning. The moisture remaining in the spotted area has acted like a magnet for loose soiling in the cleaning solvent, resulting in the localised greying which now spoils it.

Responsibility: the blame here should be taken by the cleaner, because correct stain pre-treatment is part of the cleaner’s craft skill.

Rectification: this type of fault is often easily corrected by carefully flushing the area using bar soap and the steam gun.

Tip of the month

Wedding gown woes

Many wedding gowns are washed/ wetcleaned. Fabric manufactures apply optical brightening agents (OBAs) to improve whiteness, OBAs are dyes and can be difficult to remove. Any additional OBAs can give the garment a grey appearance easily mistaken for greying. Pink and blue discolorations are also common, so do not use wash products containing an OBA for wedding gowns.