Just a damp lint-free cloth will work just fine. I've always used that for cleaning "everything". Finish off with the micro fiber cloth if you wish, but when the moisture evaporates, it should be streak free. I use this for all my screens also and never had a problem. The lcd screen is not as delicate as some make it sound.
Just get a cover like the invisishield and never have to worry about stains or marks on your notebook. I have it on all of my notebooks. Bit glossy, but it looks great to me. Plus, it provides a bit of grip to the surfaces, so it feels secure when you grab the MBA with one hand.