• If you click on Apple > Lock Screen you’ll be taken to what looks like the login window, where you’ll need to input your account password or use the Touch ID button to unlock.
• Unlocking your Watch using your Apple Watch won’t be immediately available unless the laptop sleeps and wakes up again.

This gives you a golden opportunity to grab your Apple-branded cleaning cloth (or an alternative polishing cloth) and give your keyboard a good clean. As long as you don’t graze the Touch ID button with your fingertip or accidentally type your password, you’ll stay on this screen without composing gibberish emails to your boss or loved ones.

This won’t disable the media keys at the top of the keyboard, so you’ll still be able to turn the brightness up and down or mute the volume. Keep this in mind if it seems like your screen is off after cleaning since you’ve probably just turned the brightness down.

Using the lock screen is the best way to clean your trackpad too since there’s nothing to accidentally click.

• If the imperfect logging out method isn’t good enough, the free app KeyboardCleanTool might be a better choice. This app locks every key on your keyboard, including the top row of media keys and the Touch ID button. It doesn’t disable the trackpad though, since you’ll need some way of clicking the button to disable the lock.

To use the app you’ll need to whitelist it under System Preferences (System Settings) > Security & Privacy > Privacy.

• First, click on the padlock in the bottom-left corner of the screen and authenticate, then click on the Accessibility section and check the box next to KeyboardCleanTool.

You can now use KeyboardCleanTool to lock your keyboard without logging out to give your MacBook a good clean. The author (who created powerful customization app BetterTouchTool) says the app also works great with toddlers and cats.

If your keyboard is dirty, your screen must be in a pretty bad state too. It’s important to never use household cleaners on a laptop screen since you could remove protective coatings and cause permanent damage.