I Tried Everything to Clean a Glass Shower Door … Even a Drill

If I couldn’t even descale my shower with a power tool and an award-winning hard-water cleaner, what was I supposed to make of all the people who’d claimed that they’d done it with nothing but white vinegar and a rag?

They’re not lying, I don’t think, and it turns out that any number of strategies could have gotten the job done. It’s just a matter of how patient you can be and how hard you’re willing to scrub.

Nothing beats chemistry when it comes to loosening up mineral scale. “Any acid will work,” says Paul Frail, PhD, an industrial water chemist. As long as you apply enough of any acid and leave it long enough to work (which can be minutes to hours, depending on the acid and how caked-on the scale has become), it’ll dissolve the deposits and make them easier to wipe away.

That’s why vinegar works for some people. It’s cheap, safe, and perfectly effective on calcium and magnesium—the main components of hard-water scale. There’s no special trick here: You can apply it straight out of the bottle as long as the smell doesn’t bother you. Some experts suggest mixing equal parts water and vinegar, and other recipes recommend adding a few drops of dish soap.

(And leave the bleach out of this project: It can’t help dissolve scale, and it can create a hazardous gas when it’s mixed with acids or other common household cleaners.)

I didn’t have much success with vinegar, personally. My home’s particular blend of hard water contains some iron (a yellow or orange tint in the scale is a giveaway), and vinegar fights an uphill battle against that particular mineral. It can be effective in that case, but you need more vinegar and a longer soaking time, according to Mark Jones, a retired PhD chemist who recently went through the arduous process of descaling the appliances, plumbing fixtures, and other surfaces in a house he bought.

Vinegar has another downside: “It stinks,” Jones said. For that reason alone, it never has been, nor will it ever be, my cleaning solution of choice.

Then I tried citric acid, another popular descaler. It can be food-safe, like vinegar, and it’s basically odorless. Chemically, it’s also more effective at dissolving iron—a chelating acid, in chemistry parlance. I’ve been slowly working my way through a giant bag of citric acid crystals for the better part of a decade now, doling out a few tablespoons here and there to clean my kettle, dishwasher, and other items around the house where mineral scale can build up.

Citric acid still didn’t clean my shower door, though. The problem, I later came to suspect, was that I had diluted it too much; I had put a couple of tablespoons into a quart-size spray bottle and then used only about a quarter of that watery solution on the crusty door. Even when I used it in combination with a drill brush, the scale didn’t really budge.

That supports the case for premixed hard-water cleaners: You don’t have to guess at the dosage, and they tend to include other ingredients that boost their cleaning power.