A perfect screen is made up of thousands of holes, but add one more and it's ruined. Luckily you can easily fashion a patch for an unwanted perforation.
1. Begin by trimming around the tear to create a small, clean-edged rectangular hole. Now cut a piece of screen about a half-inch larger on each side than the hole. Unravel a couple strands of screen away from the piece's four sides, and then fold the resulting "fingers" away from you.
2. Cover the hole with the patch, inserting the fingers into the mesh of the screen.
3. To complete, carefully weave the fingers, under and over, into the surrounding screen.