Gotta give you ten out of ten for trying mate!
Seriously though, 20 to 30 mins to clean a keyboard, why? Unless the keyboard is an all singing and dancing one, we wouldnt waste our time, just clean monitor, all cables, open up cpu and use compressed air to blow out all the muck and just, clean external casing and wires, clean mouse, inside as well, plug in new keyboard, job done!
Just as a point of interest, how much do you charge per pc?
Do you find that its profitable?
Video is fine apart from sound and pretty poor lighting, try doing the audio again with a mic that you plug into the sound card, much better quality, regards,
Rob