Window screens keep out bugs when you want to let in a breeze. They end up blocking one side of the window glass, though, making it impossible to clean. The simple solution is to remove the screen. The mechanism holding the screen to the window will vary by window style, but the different models are all quick to remove, and most don't require any tools.
Open the window all the way.
Look for two tabs or grips on the bottom of the screen.
Pull the tabs or grips straight up until the bottom of the screen pops out of the track.
Pull the screen inside slightly, and grab the edges of the screen.
Pull the screen down and inside to remove it from the top track.
Look for posts around the frame. These are likely screwed into the window frame and have a plastic or metal tab extending over the frame of the screen to hold it onto the window frame.
Move the tabs. If you can rotate them off the screen frame, you'll be able to take the screen off the window.
Unscrew tight screws just enough to allow you to move the tabs away freely. As you move more tabs off the screen, get ready to catch them because the tabs are the only things holding the screen up.
Look around the inside of the screens frame for objects that look like pushpins.
Pull the pins horizontally toward the center of the screen.
Move the screen away from you slightly while still holding the pins.
Pull down once the screen is out of the bottom track. Bring the screen in when you've gotten the entire screen frame out of the window frame.
Move the top screen to one side. You may have a difficult time gripping the edge because all the screen is still in the track.
Get a better grip on the screen's side as it moves out of the side track. Begin pushing out.
Move the screen out and toward the side you just removed. For example, if you pushed out the lower right corner and it is out of the track, push it out and lead it to the right. The whole screen should come free from the window frame.
Repeat Steps 1 and 2 for the bottom screen, except move the screen up a bit. This automatically removes it from the bottom track. Pull up once you've pushed one side of the screen out the window frame.