In the common convention: W is water-based cleaning, S is solvent only, WS or SW is either, and X is vacuum only.

The code is set by the fabric manufacturer and reflects how the fibre and dye respond to water. It is usually on a label beneath the cushion or on the frame.

W fabrics tolerate water-based products. Most synthetic commercial upholstery falls here.

S fabrics must be cleaned with dry solvent. Water causes watermarking, shrinkage or dye movement. Many rayons, silks and some viscose blends carry this code.

X fabrics cannot be cleaned with any liquid - vacuuming and light brushing only. Attempting anything else damages them.

Where no code exists, treat the fabric as unknown and test carefully, or refer it to a specialist. The absence of a code is not permission to use water.

Dampen a white cloth with the product, press it firmly against a hidden area for a few seconds, and look for colour on the cloth.

Choose a genuinely hidden place - under a cushion, behind a skirt, on the underside of an arm - because a test in a visible area can leave its own mark.

Any colour transfer means the fabric will bleed in use, and wet cleaning must not proceed with that product. A milder product may pass where a stronger one fails, so test what you intend to use.

Let the test area dry fully and inspect again. Some fabrics show watermarking, texture change or shrinkage only after drying, and none of that is visible while damp.

Test each different fabric on a piece. Contrast piping, cushion backs and scatter cushions are often different materials from the main body and frequently the ones that bleed.

They form where cleaning stopped and the fabric dried unevenly - the answer is to clean whole panels edge to edge and dry the piece actively.

A watermark is a ring of redeposited soil and dissolved material left at the boundary between the wet and dry areas as moisture migrates and evaporates.

Cleaning a spot in the middle of a cushion guarantees one. Cleaning the entire panel to its seams gives the moisture a defined edge that coincides with the seam and is not visible.

Even moisture application matters. Heavy application in one place and light in another produces a boundary within the panel.

Fast drying reduces the migration that creates the ring, so air movers directed at the piece are standard practice.

Where a watermark has formed, the usual correction is to re-clean the whole panel and dry it quickly and evenly.

With low-moisture tools, good vacuum recovery and forced drying - foam holds water for days and can develop odour and mould.

Upholstery hand tools apply less solution and recover more of it than carpet tools, which is why they are used rather than improvising with a carpet wand.

Cushions with removable covers can sometimes be cleaned off the foam, which removes the problem entirely - though covers should only be removed and refitted if they will go back on, since some shrink slightly.

Dry-cleaning and low-moisture foam methods put minimal water into the piece and are preferred on anything with thick foam or a wooden frame.

Active drying with air movers is essential. A cushion that feels dry on the surface can be wet inside, and the odour that follows is difficult to remove.

Stand cushions on edge to allow air to both faces while drying.

Tannin from a wooden frame or from cellulosic fibre wicking to the surface as the fabric dries - and it is caused by too much moisture.

Wooden frames and hardboard panels contain tannins that dissolve in water. If moisture reaches them, the tannin travels back into the fabric as it dries and appears as a brown stain along the frame line.

Cellulosic fibres in the fabric itself can produce the same effect, known as cellulosic browning.

Prevention is moisture control - the mark cannot form if the water never reaches the frame.

Correction uses an acidic or dedicated browning treatment applied to the affected area and dried quickly. It is more successful when addressed promptly.

On antique and valuable furniture the risk is high enough that dry methods should be the default, and specialist referral is appropriate.

No - leather needs products formulated for it, and fabric cleaners strip finishes and dry the hide.

Finished leather has a surface coating that carries most of the colour and protection. Aggressive detergents and solvents remove it, leaving a patchy, absorbent surface that then soils rapidly.

Aniline and semi-aniline leathers are far more absorbent and stain readily from water alone, so they need specialist products and technique.

Leather cleaning is a two-stage process: a mild cleaner appropriate to the finish, then a conditioner to restore flexibility. Skipping the conditioner leads to cracking over time.

Test any product in a hidden area first, as with fabric.

Bonded and coated 'leather-look' materials are different again and are usually cleaned as a vinyl rather than as leather.

By soil and use rather than by calendar - high-use seating in hospitality and healthcare needs frequent attention, and vacuuming between cleans extends the interval.

Upholstery accumulates body oils, skin, food and airborne soil. Once oil has bound dust into the fibre, restoration is much harder, so the argument for regular cleaning is economic as well as hygienic.

Vacuuming with an upholstery tool is the highest-value routine task and is frequently omitted entirely from cleaning specifications.

Protective treatment applied after cleaning buys time on spills and makes routine cleaning easier, though it needs reapplication after each wet clean.

In healthcare and food service, wipeable coverings are often specified instead of fabric precisely because the cleaning regime is easier to control.

Build the interval from observation: when soiling is visible at head and arm contact points, the cycle is too long.