Contact time
The variable people ignore and the one that most often decides the outcome — in both directions. Longer works better, and longer is also how damage happens.
In detail
Every cleaning outcome is the product of four variables: chemistry, temperature, mechanical action and time. Time is the cheapest of them and the least used. A deposit that resists thirty seconds of scrubbing will often wipe away after twenty minutes of soaking in the same solution, because the cleaner has had time to penetrate and soften it — which is why the trade instruction for burnt-on carbon starts with a pre-soak and reaches for a brush afterwards, not before. Increasing time is also the safest substitution available, because it is the only one of the four that does not involve making something harsher, hotter or more forceful. The symmetry is what makes this a concept rather than a tip. Prolonged contact is prolonged exposure for the surface as well as for the soil, and a great deal of accidental cleaning damage comes not from the wrong product but from the right product left on far too long: descaler left in an appliance past the stated time, bleach left in a stainless sink overnight, a bathroom cleaner left on stone while somebody answers the door. Where a surface's tolerance is unknown, time is the variable to be conservative with.
Why
- Soaking is explained by Contact time
- Rinsing and drying is explained by Contact time
- Burnt-on food and carbon deposits is explained by Contact time
- Bottle teat is explained by Contact time
- Sodium dichloroisocyanurate is explained by Contact time
- Kitchen is explained by Contact time
The step households skip: the surface has to stay wet for as long as the label says.
- Two-stage disinfection is explained by Contact time
Sources for this page
Sources
Care and Maintenance of Stainless Steel
British Stainless Steel Association, Stainless Steel Advisory Service, 2001 · Trade or professional body
Relied on for: That burnt-on food and carbon deposits are pre-soaked before mechanical removal is attempted, and that treatments are repeated rather than intensified. (states this directly)
Cleaning methods for stainless steel
British Stainless Steel Association · Trade or professional body
Relied on for: That where hypochlorite bleach is used on stainless steel the contact time must be minimal, and that prolonged soaking is not advisable. (states this directly)