Find an old t shirt of any color you like and cut right under the shirt sleeve. (Or follow the red line in the pic.)
Then you should have a rectangular piece of fabric left from what you cut.Then you cut the end of the shirt into 1/2' wide 2 or 2 1/2' long pieces. (Again, just follow the red lines).You can also stretch your cuts to give them a less choppy, homemade look, that's what I did.
Then fold the rest of the uncut part down to the top edge of your cuts and wala, your done!:)