I went on the hunt for a keyboard cover. Turns out that they are a lot harder to find then I thought they would be. Since every keyboard is a different shape they can't sell generic ones. I did find keyboards online that came with a clear cover that fit over each key, but since I couldn't find replacement covers, I was worried that I would have to buy a new keyboard if the cover ever got damaged. That seemed like too pricey of a solution.
I did come across a generic solution that was a simple piece of clear thin plastic that you stretched over the keyboard and fastened in the back with a weird strap system. It seemed to work for a few days, but it never stayed in place very well and ripped pretty quickly. It also cost $10 for what seemed like glorified kitchen plastic wrap, so I wasn't too keen to run out and replace it.
That was when I had my big AHA! moment. Kitchen plastic wrap.
Works like a charm. When it does get ripped or dirty, I just take it off and wrap up the keyboard again. We do have a wireless keyboard, so that makes it a bit easier to manage, but I'm sure it would work just as well with a cord. One long piece goes across the width and sticks to itself at the back of the keyboard. And then 2 short pieces going in the other direction and the whole thing is completely sealed. It has survived a juice spill without a single drop getting through to the keys.
It does help that all three of us touch type (yup, 10 year old Liam types nearly as fast as I do and has no need to look at his fingers at all. I knew that online gaming would be useful for something). Where the wrap is 2 layers thick it can be a bit hard to see the label on the keys. Otherwise there is no interference at all with using any of the keys or buttons.
Now I don't feel like I'm going to contract some strange plague every time I touch the keyboard.