Cyber Clean is one of those ubiquitous products one sees sitting on store shelves without ever giving it much thought. It's essentially a ball of fluorescent green goo that you mash into a keyboard or any similar device (obviously make sure it's turned off first), and the tacky surface picks up dirt and grime. It costs a few bucks for a small pouch, or up to $49 for a giant tub.
You're supposed to be able to literally fold the dirt and debris back into the mass and use the glob over and over again until it loses its bright green color--but that sounds a little icky. We think of it as a single-use item.