How can I remove these windows for cleaning?
Raise the inner sash about 6"  and then firmly pull the top of the it toward yourself.  The spring-loaded tracks on either side will give slightly and the top will pivot inward.  You can then tilt it to the right or left and free it.

Similar process with the outer sash although there is a section of the track down lower where the ridge that keeps the sash in is missing.  Lower it to that point and pull inward from the top.

If the window doesn't come easily, you can press the track on one side or the other with your palm to make it a bit easier.

To re-install, reverse the process.  Put the outer sash in first at the bottom, press in the top.  Slide it up.  Then put the bottom of the inner sash in, tilt it upward and press the top into place.