I used a non alcohol liquid used to clean the digital sensors of cameras. I wasn't sure if it had alcohol and all it says is that us made of bio materials :/. The cleaning went well and its more clear now, but was worried I had damaged something I wasn't able to detect. The only issue i have is with the viewfinder frame. It seems to be tipped on one side. instead of looking like this:
http://www.flickr.com/photos/mnmleung/7320083890/

it seems like crooked frame on a wall, tipped to one side. It was like that before but I could not fix it :/