http://www.lowes.com/lkn?action=howTo&p=LawnGarden/InsPrchScrn.html&rn=RightNavFiles/rightNavHowToPatching and Repairing Screens
When old screens look unattractive, try cleaning and repairing them before you purchase new ones. Often a gentle once-over with a wire brush and vacuum cleaner can make a screen look almost new. But damaged screens will not keep out insects no matter how clean they are, so patching or replacing is in order. With new screening material and a few common tools you can maintain your screens, keeping the pests out while letting the fresh air in. Unless the repairs are major, you can finish this project in just a few hours. Lowe's is happy to provide this information as a service to you.