Turn off the computer and unplug the keyboard
Shake out loose debris over a trash can
Use compressed air to blow out dust and crumbs
Remove keycaps only if the keyboard supports it
Wipe the keyboard surface with a microfiber cloth
Dampen the cloth lightly with isopropyl alcohol or water
Clean between keys with cotton swabs
Clean keycaps separately if removed
Let all parts dry completely before reconnecting
Reattach keycaps if removed
Plug the keyboard back in and test it