PristineTouch is a macOS app for disabling your input devices temporarily — perfect for cleaning your keyboard without having to shut down!
Start the app PristineTouch, your screen will show symbol and keyboard & mouse/trackpad have been disabled.
If you are running PristineTouch for the first time, you may need to grant it accessibility access. Usually, macOS will show a system dialog with instructions to do so. If it does not, go to System Preferences > Security & Privacy > Privacy > Accessibility and grant PristineTouch access.
This program does not automatically clean your keyboard. It only assists in the process of doing so.