Never use an abrasive in the bathroom

Does it work?

Disputed

Disputed rather than refuted, because the rule is correct for most bathroom surfaces and wrong for the two it is most often applied to. Publishing it as simply false would be as misleading as the over-generalisation it corrects.

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

Abrasion removes a deposit by cutting it mechanically, and whether the surface is also cut depends on relative hardness. The blanket rule treats every bathroom surface as softer than the abrasive, which is true of acrylic and of a micron-thick tap finish and false of fired glaze on vitreous china. Hardness is a property of the specific material, not of the room it is installed in.

Background

This is a good rule that has been over-generalised into a wrong one, and the interesting part is that both halves come from the same company's care sheets. On acrylic, abrasive cleansers are excluded because they damage the surface, and a dull or scratched bath is referred to the manufacturer for repair rather than to a polish. On enamelled cast iron, harsh abrasives used regularly will scratch and destroy the surface. On plated, PVD and powder-coated tap finishes, abrasives are excluded. On mirrors, no abrasive cleaner should ever be used. But vitreous china — the toilet and the basin — is described as scratch- and abrasive-resistant, and there the guidance is explicit that SOFT abrasive cleaners may be used when necessary, while strong abrasive cleaners will scratch and dull the surface. So the rule inverts within a single room, and it inverts on the two fixtures most likely to need it. The enamel sheet adds a qualification that generalises further than any of them: where an abrasive is used it must NEVER be used without water. An abrasive carried in water is lubricated and cuts less; the same powder used dry concentrates its work exactly where it will show.

What it does not do

• The permission for soft abrasives is granted by one manufacturer for its own glazed vitreous china
• Soft and strong abrasive are not defined by any measurable threshold in the guidance
• Nothing here licenses an abrasive on acrylic, enamel, plated finishes or mirrors, all of which exclude it

What to use instead

• 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.
• 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.
• Soaking — Extending contact time so chemistry can do work that would otherwise need force. Often the difference between scrubbing and wiping.