WD-40 is not a lubricant. I know the can says it does everything — lubricates, penetrates, protects, makes toast, files your taxes — but it is a solvent and water displacer first. It will quiet a squeaky hinge for about three days and then the squeak comes back louder because the WD-40 washed away whatever lubrication was left.

Here is what actually silences a squeaky hinge for months or years.

Method one: Petroleum jelly

Vaseline costs about three dollars and silences hinges better than anything in a spray can. Here is how:

1. Remove the hinge pin. Tap it up from the bottom with a nail and a hammer — it slides out.
2. Coat the entire pin with a thin layer of petroleum jelly.
3. Slide the pin back in.
4. Open and close the door a few times to spread the lubricant inside the hinge knuckles.

Petroleum jelly stays put. It does not drip, it does not evaporate, and it does not wash away. I have a bathroom door that has been silent for two years after a single application.

Method two: Bar soap

If you do not want to pull the pin, rub a dry bar of soap along the hinge pin where it meets the knuckles. Open and close the door to work the soap into the joint. Soap is a dry lubricant — it fills the microscopic gaps between metal surfaces and lets them slide without squeaking. This works best as a quick fix. It lasts a few months.

Method three: Cooking oil in a pinch

Vegetable oil, olive oil, whatever you have. Put a few drops on the hinge pin and work the door back and forth. Cooking oil eventually goes rancid and can attract dust, so this is a temporary fix. But it gets you through the night when you have a squeaky bedroom door and a sleeping partner.

What actually causes the squeak

Metal on metal friction. The hinge pin rubs against the inside of the hinge knuckles. Over time, factory lubrication wears off and the bare metal starts grinding. Rust or dirt makes it worse. The fix is always the same: separate the two metal surfaces with something slippery.

WD-40 separates them briefly, then evaporates. Petroleum jelly stays. That is the whole difference.

If the squeak persists

You might have a bent hinge pin. Pull the pin and roll it on a flat surface. If it wobbles, replace it. Hardware stores sell replacement hinge pins for under a dollar. A bent pin will squeak no matter what you lubricate it with.