The best way to clean the area under your trackpad is by using a can of compressed air. This will remove any dust or debris that may be lodged in between the keys and the touchpad. You can also use a vacuum cleaner with a hose attachment to clean this area. Be sure to hold the vacuum cleaner at least 18 inches away from the computer to avoid damaging it. The vacuum cleaners I am suggesting here are the small ones like the ones listed below;