For many years drycleaning has been associated with smelly shops. The Solvent Emissions Directive has done little to change this perception although the increasing popularity of cyclosiloxane and hydrocarbon solvents is starting to improve matters a little because these solvents are generally odourless.
When unpleasant odours do occur, they are not only irritating for the customer but also, more importantly, can provide an early warning of problems which need to be dealt with quickly before the situation worsens.
The human nose is an extremely sensitive organ and can be much more accurate than expensive meters. For example it can detect perc in the workroom atmosphere right down to only 9 parts per million (ppm) – much lower than the average exposure limit of 50ppm.
The youngest members of the cleaning team tend to have the most sensitive noses and it worth training staff to detect different types of odour, from dank sewer smells, to those akin to cats’ urine and on to pungent smells of burnt baking and highly acidic chlorine compounds from an overheating perc still. The worst smells often come from bacteria breeding on animal proteins and these can lead to "stinking machines" that deter customers from even entering the shop and odours of vomit which really can stink the place out.
The solution lies in early detection and correction.

Bacteria feed on remains of protein stain
Fault: These white trousers were returned because they were still marked but despite recleaning they were brought back a second time because the stain was still there and had developed a putrid smell.

Cause: Even perc, which is the strongest drycleaning solvent, will not dissolve protein stains such as custard or gravy, or vegetable dyes, (such as red wine, beetroot and blackcurrant). These must be pre-treated, which is why the three-bottle kit always contains a protein remover and a tannin remover. There is little risk of colour damage on a pair of white trousers.
Responsibility: The cleaner is generally responsible for correctly attempting stain pre-treatment, especially when the risk is low (as it is here).
Rectification: The trousers can be post-treated to reduce the staining and this ought to cure the odour problem. There are special post-treatment reagents for stain removal, which are stronger than those for pre-treatment.

Fungus develops on weft of curtain fabric
Fault: These curtains smelled slightly musty before cleaning, which did not then worry the cleaner. Four weeks later the customer returned them, saying the smell had returned and that the curtains were still marked.
Cause: The marking, short lines of deep brown discoloration, followed the horizontal (weft) yarns in the weave in every case. This symptom is typical of fungal growth, which is like mildew but produces lines not spots as it grows on one of the weft yarns.
Responsibility: This growth is too well established to have occurred in the cleaner’s shop. The curtains have been at a cold, damp window where a few fungal spores, probably airborne, have landed and started to breed. The first drycleaning will probably have killed the active spores but if the curtains are re-hung in the same place, then the spores in the area will have re-colonised the fabric. The musty odour is typical of fungal "excrement". The responsibility here should remain with the owner.
Rectification: Re-cleaning will kill the new growth but would be pointless until all spores have been removed from the curtain’s location which might be a task for a specialist house cleaner.

High still temperature causes chemical attack
Fault: The cleaner became increasingly aware of sharp pungent smells on textiles and in the shops. The water from the perc machine’s water separator was now blue-green rather than water-white and the amount was increasing.
Cause: Both the blue-green separator water and the increased water flow indicate that the copper cooling coil in the still condenser has suffered a chemical attack as many copper compounds are shades of blue or green. The temperature in the still is too high and this high temperature combined with certain types of soiling and " cracks" the perc molecule to produce hydrogen chloride. This is a very acidic, pungent gas that tends to dissolve in the water from the still, which has a pure perc vapour. The resultant hydrochloric acid then attacks the still condenser. It not only affects the water colour but the copper coil will develop a pinhole and leak water drops in the recovered solvent going to the water separator.
Responsibility: The cleaner is responsible for daily checks on the colour and flow of the separator water.
Rectification: Reduce the still temperature, either by turning down the thermostat ((electrically heated stills) or in a steam-heated still, reducing the steam pressure in 0.1bar steps.

Check the lint filter for blockages and holes
Fault: The cleaner noted a marked increase in solvent odours and solvent use but the engineer found that the machine was solvent-tight. The problem led to many complaints of poor drying and solvent odours on garments.

Cause: There was a small hole in the lint filter and although the filter was cleaned before each load, enough lint was getting through the tiny hole to progressively block the solvent recovery head in the drying circuit. This reduced the head’s performance so the flow of solvent from it was very low, even though the garments were still wet with solvent. As often happens, the dryness controller detected the low flow rate and stopped the cycle well before the load was properly dry.
Responsibility: The cleaner is responsible not only for clearing the lint screen before every cycle but also for checking for holes in the screen and for a poor fit in the housing.
Rectification: The garments with a residual odour of solvent should be processed with an "extra-dry" cycle, once the recovery head has been cleaned and de-linted.

Smoke damage needs a specialist detergent
Fault: Several batches of smoke contaminated textiles still smelled of smoke after cleaning even though they had been processed with an increased dose of the shop’s expensive detergent.
Cause: Smoke damage contains tars and carbon particles. If these are not removed completely they will cause the smoke smell to persist as has happened here. A strong anionic detergent with high suspending power is required to break the bond between oil and fabric. The detergent used for normal retail work is probably cationic which will not be as effective on smoke stains.
Responsibility: The cleaner is responsible for devising and executing the best process for smoke-damaged work. This requires a purpose-designed "smoke-detergent". Even this might not remove every last trace of odour but providing that the cleaner has used the best possible process with the right detergent at the right dose, he should not be held responsible for lingering smells.
Rectification: The cleaner needs to get the processing of smoke-damaged work right first time because any remaining carbon particles will tend to re-deposit onto the textiles and become irremovable.
Re-cleaning with the right process will not reverse the result of an inadequate process. Smoke damaged work should be handled in batches and the cleaner needs to sniff the first batch when it comes out of the machine before proceeding with the rest of the work.

Water separator should be checked daily
Fault: On some days all work had a distinctive, unpleasant mouldy odour.
Cause: Algae that breed in the water separator often cause mouldy odours. These and other growths will be visible through the sight glass, indicating that the separator should be cleaned thoroughly and re-filled immediately. These growths also cause water drops to carry over into the separator, leading to a steady increase in complaints of shrinkage in wool hair garments.
Responsibility: The cleaner should check the water separator daily to prevent unwanted growth.
Rectification: Re-cleaning the separator will usually remove mouldy smells and kill spores.