What can't I use Universal Cleaner on?Updated 10 days ago

Koh Universal Cleaner is a higher alkaline solution. The alkaline formulation is what cuts through cooking grease and organic matter, making it easier to clean, and it is also what makes it reactive with soft metals. Raw aluminium, copper, brass and zinc can discolour, tarnish, oxidise, etch or develop a cloudy film on contact. The reaction is chemistry, not a product fault, and any alkaline cleaner will do the same thing to those metals. Sealed, lacquered or coated versions of the same metals are usually fine to clean, but spot test a hidden area first to confirm the protective layer is still intact. For raw brass, copper or zinc, use a polish made for that metal instead.

No. Avoid Koh Universal Cleaner on aftermarket window tint films such as car window and privacy films, on protective window films, and on specialty glass coatings such as EnduroShield. These can peel, cloud, lift at the edges or strip when an alkaline cleaner sits on them. Factory-installed automotive tints are usually more robust than aftermarket films, but check with the manufacturer before using any alkaline cleaner on them. On coated or treated glass, the film or coating manufacturer's own cleaning guidance is the one to follow. Plain untreated glass and mirrors are fine and one of the surfaces Universal Cleaner is best on.

For raw brass, copper, zinc or bare aluminium, use a polish or cleaner formulated for that specific metal rather than an alkaline all-purpose cleaner. For aftermarket window tints, protective films and specialty glass coatings such as EnduroShield, follow the film or coating manufacturer's own cleaning instructions, which usually call for plain water or a mild cleaner on a Koh glass cloth. Sealed, lacquered or powder-coated versions of those same metals are usually fine with Koh Universal Cleaner once you have spot tested a hidden area, and so is untreated glass.

Spot test it. There are too many specialty finishes, factory coatings and vintage materials in modern homes to list every incompatible one. If a surface is unfamiliar, unusual or valuable, spray a small amount of Koh Universal Cleaner on a hidden area, wait a few minutes, wipe with a Koh cloth, and check for colour change, sheen change, etching or texture change before committing to the whole surface. Five minutes of testing beats a damaged benchtop. It is especially worth doing on natural stone, aged sealants, soft furnishings and anything the manufacturer labels a specialty finish.