Hi, leeneia,
If you cover electronic components with plastic, they are likely to overheat.

IBM used to make a mechanical keyboard, and it was a favorite among those who were fussy about computer equipment. It had a feel that was much closer to the feeling of an electric typewriter keyboard (an IBM Selecitric keyboard, to be exact). I had one at work, and it really was wonderful to use. Later on, when it was impossible to get mechanical keyboards, I satisfied myself with Microsoft keyboards, which are pretty good.

Joe