I just spent an hour cleaning my keyboard. It isn't perfect, but I ran out of q-tips. I have plenty of alcohol, but I really need q tips. It isn't as grubby as it was. If you really want a grubby keyboard, take a laptop to school and let kids use it. I retired two years ago. It took me a while to decide I was going to use it. It is old but the reason I stopped using it was because it didn't have enough storage space, operating space, and usb ports. So my lovely desktop computer in the house solves those problems.
The laptop in my art room (separate building) lets me connect to the internet out here as long as I bring my aircard out here.