I use windex too. They make windex which is safe to use with window tint, meaning it has no ammonia in it. If you were really concerned, you could use that. I've had no issues with using the regular windex though.
"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