It is not recommended that you try to wash your laptop keyboard in a sink or dishwasher. The water could get inside the computer and cause damage, and the pressure of the water could push dirt and dust further into small crevices where it's hard to clean. You can use a slightly damp cloth to wipe down the surface of the keyboard, but be very careful not to get any liquid into the cracks between the keys. If your laptop has a touchpad or trackball, you can also clean these with a damp cloth. Just make sure that they are completely dry before using them again.