Before cleaning a textile consider the following:
- Why does the textile need to be cleaned?
- Will the textile benefit from cleaning?
- Will cleaning remove any important elements of its history?
- Is the textile strong enough to withstand the treatment?
Seek the advice of a conservator as cleaning, especially wet cleaning, may weaken some textiles. Chemical cleaning should be undertaken only by someone experienced in the cleaning of historic textiles and only an experienced conservator should attempt to clean painted textiles (such as flags and banners) and weighted silks.
Most textiles in collections have been used and washed through their useful life and come into collections in a physically worn state. For many clothing items such as cottons and linen Manchester, past treatments often included starching. Starch penetrates textiles and stiffens them when ironed. As starch is detrimental to textile fibres its removal will help in the long-term preservation of textiles. It can be gradually washed out on the occasions when wet cleaning is required. Do not re-starch an old textile.
Remove loose dirt and dust from a textile before considering any other treatment. As with all treatments, carry out vacuum cleaning only when necessary, such as when preparing objects for display or storage. Very brittle or insect-damaged textiles are likely to be too fragile for vacuum cleaning. Have very fragile textiles assessed by a conservator before attempting any cleaning. Do not use beater-type vacuum cleaners and vacuum brush attachments on textiles.
Use a vacuum cleaner with adjustable suction and a soft brush. Mini attachments for vacuum cleaners are useful tools for detailed and careful cleaning. Either a variable speed motor or perforations in the hose system will allow the suction to be controlled. These controls should be at the user’s hand so that adjustments can be made immediately the need arises. A low suction car vacuum cleaner is suitable.
When using a vacuum cleaner on textile material:
- fit the end of the vacuum cleaner with a protective screen between the hose and the textile. A piece of muslin, nylon stocking or fine gauze, held in place by string or an elastic band are suitable for this purpose;
- hold the nozzle slightly above the surface of the textile while cleaning; and
- adjust the amount of suction applied to match the fragility of the textile.
As an alternative to placing a screen over the nozzle of the vacuum cleaner, place monofilament screening, such as an embroidery frame fitted with tulle, over the textile and move the vacuum cleaner over the screen. In this way, dust is drawn through the screen but neither the fabric nor its fibres are drawn into the vacuum cleaner. Bind the edges of the screen to prevent snagging on the textile.
Do not wash textiles in water as a matter of course nor as part of an annual maintenance or cleaning program as this process can result in fabric loss, the loss of historic information and can permanently alter the look and feel of the textile. Avoid water cleaning textiles unless absolutely necessary for the survival of the textile in question. Do not wash heritage textiles in a washing machine.
In addition to considering the general points mentioned in the preamble to dry cleaning (see above), determine the colourfastness of dyes and the effects of washing on different fibre types, different weaves and on non-textile components before wet cleaning historic textiles.
Even the ‘safest’ of fabrics, such as white cottons and linens, are susceptible to damage during washing. It is not always possible to ascertain areas of weakness in an old textile and the resultant fabric loss can be significant. For example, dark coloured stains of an unknown origin may fall out during washing, leaving gaping holes in the textile. In addition certain finishing agents, incorporated in textiles to give them a particular look, may be washed out in water, irreversibly altering the appearance and characteristics of the textile.
Assessing coloured textiles is difficult as there are no foolproof tests to determine the colourfastness of the component colours. In the method described below, caution is advised as dyes may run unexpectedly, either in the wash or as the textile dries. If a soap is incorporated into the wash solution the resultant pH change (acidity level) may be enough for dyes that were previously set to become soluble and be lost.
Many textiles are made up of combinations of different fibre types, with cotton-silk and cotton-wool being common examples. Before washing consider the ‘wet properties’ of different fibre types and the reactions of individual fibre types to different pH conditions which result from using soap solutions.
Fabrics of the same fibre type but of different weave tension are also found in textile collections. Linings, for example, often have a different weave to the outer fabric. Washing in water may produce different shrinkage rates for the combinations, resulting in tensions in the textile between the differently woven fabrics. A further problem may arise if dust and dirt are trapped between the lining and the textile. Permanent staining of the outer textile has occurred when such textiles have been washed (Finch and Putnam 1985).
Bearing the above in mind, undertake washing only if the textile is likely to deteriorate due to the presence of dirt or stains (Figure 13). To ensure that this type of treatment will benefit the textile, seek the advice of a conservator before washing. Regard washing as a one-off process which is followed up by correct storage or display to avoid the need for further washing in the future.
Surface clean textiles using a vacuum cleaner and screen (as described above) before wet cleaning. Strong white textiles, such as linens and cottons, can usually be washed by the method described below. Precautions must be taken however before washing coloured fabrics. In particular, test each colour for fastness before any form of wet cleaning. To do this:
- use an unobtrusive part of the textile for this test;
- place a square of blotting paper or folded absorbent paper tissue under the colour test point;
- dip a cotton bud into the soap solution to be used for cleaning. The cotton bud should be only slightly damp;
- hold the moistened cotton bud on the test colour for a short time under light pressure;
- check the cotton bud and the paper below for transfer of colour; and
- repeat the test on all colours present.
Do not wash the textile if any colour transfers to the cotton bud or paper below. Consult a conservator in this instance.
Other checks are also necessary, as some attachments are not stable in water. Buttons and sequins made of gelatine and casein, for example, swell and disintegrate in water. Some fabrics, such as pressed velour, glazed chintz and crepes are not suited to water cleaning and treatments should be carried out only by a qualified conservator.
Equipment for Wet Washing
To wet wash textiles, the following equipment is needed:
- a large flat tray;
- nylon fly screen or nylon curtain material, larger than the textile, to support the textile when lifting it;
- enough good quality water to cover the textile by about 20mm;
- a pure soap;
- clean, white towels to remove excess water from the textile; and
- fans and/or a cold air blowing hair drier.
The washing tray, such as a photographer's tray or bath, should be large enough to allow the textile to lay flat while immersed. Improvisation may be needed, especially if large textiles are to be washed.
Never lift unsupported wet textiles, as they are extremely fragile and the weight of the water could cause irreparable damage. Ensure that the support is lifted not the textile. Two or three people may be required to lift the support evenly when handling larger textiles.
Although distilled or deionised water is recommended for all stages of cleaning, softened tap water can be used for washing and for the first two rinses as long as distilled or deionised water is used for the final rinse. Bore water is not suitable and rainwater may contain impurities and particulate matter that could damage the fabric.
Commercial varieties of pure soaps are available. Use about five grams (about one rounded dessertspoon) of soap per 8 litres of water. In most situations where washing is deemed essential, conservators use a non-ionic, pH-neutral soap solution. Before washing, establish which type of soap solution is best for the textile in question. Do not use commercial detergents because they often contain harsh additives which are damaging to fragile textiles.
Wash, rinse and dry textiles in a clean, dust-free room, according to the following procedures:
- dissolve the soap in a small quantity of warm water. Add this to the cold or tepid water in the tray and mix thoroughly;
- place the textile on its support and gently lower it into the solution, ensuring that the textile is wet evenly;
- gently press the textile all over with the palms of the hands or with the aid of a small sponge. This creates a mild suction which helps to remove dirt;
- never rub the textile or dip it in and out of the solution;
- if the textile is relatively strong, leave it to soak for five to ten minutes, then press again; and
- note that colours can run with prolonged immersion, even after passing the colourfastness test.
Rinsing is necessary to remove the soap solution, prevent dirt from resettling into the textile and to remove potentially damaging materials. To rinse the textile, follow these steps:
- using the support, remove the textile from the wash solution and place it in clean water;
- repeat the pressing action with the palms of the hands or with a sponge;
- change the water again and repeat the process as often as required (usually three times) until all traces of soap and dirt have been removed; and
- use distilled or deionised water for the last rinse.
Dry textiles as gently as possible. Never use sunlight or artificial heat. When drying textiles, observe the following guidelines:
- dry textiles right side up;
- using the support, remove the textile from the last rinse water and allow it to drain for a short time before placing it on clean, dry white towels;
- cover the textile with more towels and gently press to absorb excess moisture. Gentle pressing should minimise any flattening of the weave;
- repeat the process with fresh dry towels;
- the textile can be dried on dry towels or placed onto a membrane such as a framed flyscreen which will allow a good air flow during the drying process;
- fans can be used to increase the air flow; or
- use a hairdryer on a cool and a low speed setting to accelerate the drying process. Avoid spot drying. While using a hairdryer, smooth folds or creases with the other hand. With three dimensional textiles, such as dresses, separate layers of fabric and lift the sleeves so that air can pass through.
Drying in the above manner usually removes any need for ironing, a very harsh treatment that should only be carried out if absolutely necessary. If ironing is deemed necessary, observe the following guidelines:
- iron the textile while it is still slightly damp (not wet);
- insert a cloth between the fabric and the iron;
- support the fabric fully, as while damp, it may not be able to support its own weight;
- set the iron at its coolest possible setting. Never use steam;
- never iron folds and creases into a textile as the fibres will eventually break along these lines; and
- make small covered pads to make ironing sleeves or small spaces easier.
Do not starch historic textiles as it attracts insects and stiffens the fibres, which may lead to their eventual breakage.
Do not further treat stains that remain after washing. Do not try spot cleaning or bleaching as these usually weaken the textile and may form a halo-like effect around the stain
Minimal intervention is recommended but in some instances support stitching will prevent further deterioration of a textile. Minimal stitching should be used to stabilise a textile and it is recommended that a conservator be consulted for advice.
If stitching is undertaken, note the following:
- match the repair thread with the textile, both in colour and denier. A fine silk will require a fine silk thread whereas a woollen tapestry will require a coarser woollen thread;
- use a needle that is as fine as possible and take care to stitch between the threads as opposed to stitching through them. The type of stitch will depend on the type of stabilisation required;
- balance the stitch tension so that it is not too tight so as to damage the fibres nor too loose that it is ineffective;
- use running stitches to join two layers of fabric together, with equal lengths above and below or perhaps with minimal stitches on the surface; and
- periodically secure the running stitch with a back stitch. Use a herringbone stitch to stabilise frayed edges and couching to secure loose threads.