I spent three years wiping my bathroom mirror with a towel after every shower. Three years of stepping out of a warm shower into cold air, standing there in a towel, doing the thing where you wipe a circle just big enough to see your face. It never occurred to me that there was a way to stop it from fogging in the first place.

Then I saw a guy on YouTube rub shaving cream on his mirror. I thought it was a prank. It was not. I tried it. My mirror stayed clear for two full weeks after one application. I have not wiped fog off a mirror since.

The Shaving Cream Method

You need the foam kind — not gel, not the clear stuff. Regular white foaming shaving cream. Barbasol, the cheap stuff. Dollar store brand. Whatever.

1. Squirt a dollop about the size of a quarter onto a dry microfiber cloth or paper towel.
2. Rub it all over the mirror in circular motions. Get the whole surface. It will look like you are smearing white goo everywhere. That is correct.
3. Take a clean dry cloth and buff it off completely. Keep buffing until the mirror is clear with no streaks. It takes a minute or two. Put a little effort in.
4. That is it. The mirror is now coated with a microscopically thin layer of surfactant — the same ingredient that makes shaving cream foam — that prevents water vapor from condensing into droplets.

I shower with the door closed, water as hot as it goes, and the mirror stays clear. Not “mostly clear.” Clear. I can shave or do skincare immediately after showering.

How Long Does It Last?

In my bathroom — one person, one shower per day — the coating lasts about two to three weeks. If you have multiple people showering back to back, maybe ten days. Reapply whenever you notice fog starting to creep back in. It takes under two minutes.

One can of shaving cream will last you years doing this. I am still on the same can I bought in January.

Other Things People Try (That Also Work)

• Dish soap: A single drop on a cloth, buff on, buff off. Works for about a week. The advantage is everyone has dish soap. The disadvantage is streaks — it is harder to buff completely clear than shaving cream.
• Rain-X: The car windshield treatment. It definitely works on mirrors too. Lasts longer — maybe a month. But it smells like a gas station and the fumes in a small bathroom are not great. I tried it once. The results were good but I could smell it for two days.
• Toothpaste: Non-gel white toothpaste buffed on and off reportedly works. I have not tried this one because I like my shaving cream method and do not want to put toothpaste on my mirror.

What About Heated Mirrors?

Some fancy bathrooms have built-in heated mirrors that prevent fogging electrically. They are great. They also cost hundreds of dollars to install. Shaving cream costs two dollars. I know which one I am choosing.