How can I clean my iPad LCD? I accidentaly touched it!

I have an pad air (WiFi), but i accidentally dropped it.

So i ordered the new glass digitizer. 1 day before it was delivered i removed the old glass.

Today the new glass arrived, so i wanted to install it right away. everything works fine. but i have one problem i haven't glued (stickers) it in place yet. Because there were a couple of fingerprints on the LCD, now i cant get it clean.

i tried with some alcohol, microfiber cloth, toilet paper, vapor from my breath. but now its more dirty then before.

does anyone have a solution for this?

p.s. sorry for my bad English, its my second language.

thank you in advance.