Cream cleaners ruin uPVC

Does it work?

Disputed

Disputed rather than refuted because the claim is half right in a way that matters. Cream cleaners do dull the gloss with heavy use, which is what its believers have seen; the manufacturer nonetheless permits occasional non-abrasive use on a stain. A verdict of refuted would tell a reader the concern is baseless, and it is not - it is a dose they are describing, not a prohibition.

This is a verdict on whether the technique is effective. Whether it is safe on a particular surface is a separate question, answered below.

Where not to use it

Why it works

The claim's implied mechanism is abrasion: a cream cleaner carries fine abrasive particles, uPVC is a relatively soft polymer, so the particles dull or scratch it. That is the right mechanism and the manufacturer confirms the effect - excess use affects the GLOSS FINISH, which is the language of a surface being progressively micro-abraded rather than chemically attacked. Where the claim goes wrong is in converting a dose-dependent effect into a prohibition. The guide's own distinction is between a NON-ABRASIVE cream cleaner used occasionally on a stain and heavy repeated use, and it separately reserves its absolute prohibition for a different mechanism entirely: solvent attack on the polymer.

Background

Consumer advice on uPVC splits into two confident camps: cream cleaners destroy it, or cream cleaners are the answer to everything. The manufacturer's own trade guide agrees with neither, and its position is more useful than both. Routine cleaning is soapy water. Where a stain will not come off with that, a domestic NON-ABRASIVE cream cleaner MAY remove it. The condition is not decoration: these should not be used to excess, because they can affect the gloss finish. So the claim is right about the failure mode and wrong about the prohibition - overuse dulls the surface, which is exactly what somebody who cleans their frames with cream cleaner every week would eventually see. Two carve-outs get lost when this is repeated. Decorative finishes, woodgrain foils in particular, are referred back to the supplier rather than covered by the permission. And the thing the guide actually prohibits outright, twice and in capitals, is different: on no account should solvent-based cleaners be used. The hardware is a third answer again.

Conditions

• non-abrasive cream cleaner only
• for stains soapy water has not removed, not as routine
• used sparingly, because excess affects the gloss finish
• not on woodgrain foils or other decorative finishes

What it does not do

• The permission is the manufacturer's for its own profiles, not a general clearance for all uPVC
• It does not extend to woodgrain foils or decorative finishes, which go back to the supplier
• It says nothing about restoring a gloss finish already dulled by overuse
• Solvent-based cleaners remain prohibited outright, which is a different and stronger instruction

What to use instead

• Detergent — A surfactant-based cleaner. The general-purpose answer for greasy and particulate soil, and the correct first choice far more often than any specialist product.
• uPVC — The commonest window frame in the UK and the material with the most confident wrong advice attached to it. The manufacturer permits a cream cleaner — sparingly, and not on woodgrain.
• Mild cream cleanser — A liquid carrying a fine soft abrasive. The trade answer for water marks and light staining on stainless steel — and not the same thing as scouring powder.