Here's a [guide|132050|guide|new_window=true] for a similar model. You can use a flat pick like a guitar pick or something similar to separate the keycap from the mechanism beneath it. The space bar is a little trickier than the other keys because it's typically held in place by more clips. If you can safely get the keycap off without damaging anything you'll want to keep track of its orientation so you can reinstall it correctly after cleaning beneath it. Good luck!