The following images are ones we have taken at client offices before we have cleaned.  The images are typical of what we find with each new client!  Do your computers look like this?

What you can see is the visible dirt, dust and grime which sticks to the keyboards - all this comes from the grease from your skin (or anyone else who uses your office equipment) rubbing and sticking onto the keys, and all the grime around the office sticking to it and accumulating.

What you can't see are the millions of microbes, bacteria and viruses that are on the surface of all the keys, in between the keys, and beneath the keys in the cracks you can't normally get to.

Imagine what you're touching each time you use your keyboard and 'phone!