I once killed a perfectly good mechanical keyboard by trying to clean it. Unplugged it, ran it under the faucet, scrubbed with dish soap, set it in the sun to dry. Three days later I plugged it back in and nothing happened. A hundred and twenty dollars down the drain.

Keyboards are filthy. Studies have found more bacteria on the average keyboard than on a toilet seat. But they are also delicate. The trick is getting the crud out without shorting the circuits.

What you need

• Keycap puller (plastic ones come with most mechanical keyboards, or two dollars online)
• Canned air or an electric duster
• Isopropyl alcohol, 70% or higher
• Cotton swabs and a soft toothbrush
• A bowl of warm water with a drop of dish soap
• Microfiber cloth

Step by step without shorting anything

1. Unplug it. Or turn off Bluetooth. No power, no chance of a short.
2. Take a photo of the layout. You will forget where the function keys go. Everyone does. Snap a picture with your phone.
3. Pull the keycaps. Start from a corner. The puller clips under two sides — squeeze and lift straight up. Do not twist. Twisting breaks the stems underneath.
4. Soak the keycaps. Drop them in the bowl of warm soapy water. Let them sit for thirty minutes while you clean the board.
5. Blow out the base. Hold the keyboard at an angle, spray canned air in short bursts. Do not invert the can — the liquid propellant will spray out and freeze whatever it touches. Keep the can upright.
6. Clean between switches. Dip a cotton swab in isopropyl alcohol, squeeze out the excess, and gently clean around each switch housing. The alcohol evaporates quickly and will not damage electronics.
7. Scrub stubborn grime. A dry toothbrush gets into the corners. Gentle circular motions. Do not press hard enough to bend switch stems.
8. Rinse and dry keycaps. Dump the soaking water, rinse the caps under clean water, spread them on a towel overnight. They must be completely dry — water trapped inside a keycap will drip into the switch when you put it back.
9. Reassemble. Use your photo. Press each keycap straight down until it clicks.

What never to do

• Never spray cleaner directly onto the keyboard. Moisture seeps into the circuit board.
• Never use a vacuum cleaner on your keyboard. Static electricity can fry components.
• Never put keycaps in the dishwasher. The heat warps them.
• Never use acetone or nail polish remover. It melts ABS plastic.

My replacement keyboard is three years old now and looks new. I clean it every three months. It takes twenty minutes and costs nothing in supplies.