By Robin Murphy
Bleach has a reputation.
I’ve had plenty of people ask whether we use it, and the question usually comes up when they’re talking about something they consider especially dirty. A shower. Grout. A toilet. Something stained. Bleach is what we reach for when ordinary cleaning somehow doesn’t seem serious enough.
Which makes the CDC’s instructions particularly interesting.
If a surface is visibly dirty, the CDC says to clean it before disinfecting it with bleach. Dirt and other material on a surface can interfere with the disinfectant doing its job.
Clean first. Bleach second.
That sounds backward because we’ve given bleach several different jobs and called them all cleaning.
Cleaning removes soil and other material from a surface. Disinfecting is a different job. Bleach, when used correctly, can be a very effective disinfectant. It can kill many microorganisms, which is one reason it has earned the reputation it has.
But bleach has another talent that may be even more persuasive to our eyes.
It makes things disappear.
Put bleach on a discolored area and sometimes you can watch the color fade in front of you. There was a stain. Now there isn’t. Few cleaning products give us a more convincing before and after.
Except that isn’t quite what happened.
Bleach is an oxidizer. When it acts on many colored compounds, it can change their chemical structure so they no longer absorb and reflect visible light in the same way. In other words, what your eye recognizes as the stain can disappear because the molecules responsible for its color have changed.
That doesn’t necessarily mean everything that was there has been physically removed from the surface.
And I think that distinction explains some of bleach’s hold on us. Most cleaning happens without much drama. You wipe. You scrub. You rinse. Soil ends up on the cloth or in the water and eventually leaves the house.
Bleach can give you a magic trick.
That visual change is real. So is bleach’s ability to disinfect when it’s used correctly. The mistake is assuming that because bleach is very good at some jobs, it must be the best answer whenever something looks especially dirty.
It isn’t especially good at every kind of soil. Grease is still grease. Mineral deposits are still mineral deposits. Soap residue still has to be removed. And if the goal is disinfection, visible dirt may need to be cleaned away before the bleach ever gets its turn.
None of this makes bleach less powerful. It makes the word powerful more specific.
Bleach can disinfect. It can whiten. It can make a stain disappear before your eyes. But disappearing and removing aren’t always the same thing.
