dont clean it while its on the tank... as long as you rinse it good, it'll be fine. You'll find that life is much easier without glass tops or hoods. I learned to hate mine real quick.
"What, exactly, is the internet? Basically it is a global network exchanging digitized data in such a way that any computer, anywhere, that is equipped with a device called a 'modem', can make a noise like a duck choking on a kazoo." - Dave Barry