Hi, I have an AOC monitor and I used a cotton cloth to lightly clean some dust, however for some reason I started to get some smudges on the screen which I don't get in other areas. I tried to use a microfibre cloth to clean the smudges but they just start to spread over and get worse. My only option is to use some type of screen cleaning liquid but I am bit skeptical to use anything in fear of making it worse. AOC advises windex ??? Any ideas.