Rebus #169 When Im Cleaning Windows

If your new to Rebuses, you can read how to solve a Rebus here (link opens in a new window).
Do you need a little help? Click to reveal a clue to the above Rebus.
A clue to help decipher the hidden meaning – This is a two part puzzle, you have the word “Window” and a section highlighted “Ow”. What would cause you to say “Ow”?