Having to whipe down your scale after each use can be a pain. I find that placing saran (plastic) wrap over the scale, including the key pad does the trick.
With clean hands, simply place a large enough piece of plastic wrap over the scale and keypad.
The plastic wrap usually weighs less than nothing so you won't need to reset the scale to zero. Once you've measured out your item, remove the food by lifting the plastic wrap. Now you can either cook it or wrap it up and refrigerate/freeze it.