First off, I make it a point to clean my booth before and after each show, so that equates to about twice every 6-ish weeks. Having a mess in the booth just drives me nuts, and since I spend enough time there, it is important. So I vacuum the floor, windex the windows, take out the trash, etc. You just have to do it, it is part of the job, and it helps you do your job to the best of your ability.
As for food in the booth, we have plenty of table space that isn't over a console. We (the SM, sound op, and I) keep a bowl of candy. Usually all three of us have water bottles, and quite often (especially for matinees) the SM and I come in with lunch. We have a much more controlled environment though than most schools, our booth is not tramped through by many people, no one who isn't supposed to be there, so it is a lot easier for us to be careful about where food is, and keeping it away from important equipment.
As for food in the booth, we have plenty of table space that isn't over a console. We (the SM, sound op, and I) keep a bowl of candy. Usually all three of us have water bottles, and quite often (especially for matinees) the SM and I come in with lunch. We have a much more controlled environment though than most schools, our booth is not tramped through by many people, no one who isn't supposed to be there, so it is a lot easier for us to be careful about where food is, and keeping it away from important equipment.