Light switch
A hand-contact point with a live electrical device behind it, which changes the method more than the material does.
Precautions
- Disconnect from the power supply first
- Check the manufacturer's instructions
Start here
What this is, what tends to go wrong with it, and what to do about it.
Made from
What tends to go wrong
- Dustvia its material
Mostly textile fibres and skin, held by static as much as by gravity — which is why a dry cloth on a plastic surface makes it worse.
Why it is difficult: Static and dust, Mechanical action and abrasion, Why different surfaces get different dirt, Surface roughness
A concentrated water-soluble dye with nothing else in it. Nothing has to be emulsified or dissolved — the only question is whether the surface has taken the colour up.
Why it is difficult: Capillary absorption, Dye migration and colour bleeding
A sticky, yellow-brown tar film deposited everywhere at once. It is the reason a room smells after everything visible has been cleaned.
Why it is difficult: Adsorption of odour molecules, Solubility and polarity
Coloured by turmeric in most prepared mustards, and curcumin is a pH indicator — which is why an alkaline cleaner turns a yellow mark red.
Why it is difficult: pH indicators in stains, Fat-soluble pigments, Photodegradation, Pigment retention
The commonest cleaning problem that is not dirt. The tackiness is the plastic's own additive arriving at the surface, which is why wiping it off works for a week.
Why it is difficult: Plasticizer migration, Damage versus soiling
The science behind this: Solvent crazing, Static and dust, Solvents and polymers, Plasticizer migration
In detail
Switches appear on the food regulator's list of frequently touched items to be cleaned and disinfected regularly, for the same transfer reason as door handles: they are touched constantly, they are rarely inspected, and nothing about them announces when they need attention. What separates a switch from a handle is what is behind it. The plate is a cover over mains wiring, and liquid applied to the face can pass the edge of the plate. That makes this a case where the standing rule against spraying a product onto the thing applies with particular force: a cloth dampened and wrung out away from the switch, rather than a spray onto it. The same principle applies to screens, appliances and light fittings, for the same reason.
Related
- Light switch is made from Household plastics
Sources for this page
Sources
Safe Method: Cleaning Effectively (Safer Food, Better Business)
Food Standards Agency, United Kingdom · Government or regulator
Relied on for: That items people touch frequently — work surfaces, sinks, taps, door handles, switches, can openers, telephones and scales — should be regularly washed, wiped and disinfected because hands carry contamination from them to food and to other areas. (states this directly)