Fingerprints

In detail

A fingerprint is a deposit of skin oils, sweat residue and whatever the hand last touched, left where the ridges of the fingertip made contact. Chemically it is an oily soil, which is the whole reason it resists a dry cloth and a rinse: water cannot wet or carry oil, so wiping with water redistributes the mark rather than removing it. The two routes that work are the ones that always work on oils — a surfactant, which is what detergent in warm water provides, or a solvent that dissolves the oil outright, which on stainless steel means a hydrocarbon solvent such as methylated spirit or isopropyl alcohol. Both are recommended by the stainless steel trade association, and the choice between them is practical rather than chemical: detergent needs rinsing and drying, and a volatile solvent evaporates without a residue, which is why it suits vertical panels and anything where a drying mark would be as visible as the fingerprint was. Nothing prevents recurrence except not touching the surface, which is why proprietary polishes for the job are sold on the basis of minimising re-marking rather than cleaning better.

What works

• Detergent is effective against Fingerprints Supported

• Solvent wiping is effective against Fingerprints Supported

• Microfibre cloth is effective against Fingerprints Established practitioner practice

• Re-lubrication is effective against Fingerprints Supported

  The counter-intuitive one: a fingerprint on bare steel comes off with oil, not with detergent.

Why

• Fingerprints is explained by Surfactancy

Hacks and claims involving this

• Newspaper for cleaning glass Established practitioner practice
• Vinegar for mirrors and glass Does not work
• Toothpaste as a metal polish Does not work
• Washing-up liquid on leather Does not work
• Baking soda paste for marks on painted walls Supported
• Alcohol cleaners are gentle, so they are safe Disputed
• Spraying cleaner onto a screen or keyboard Does not work