Lay a shirt flat on the work surface. Cut just below the armpit from one side to the other with the scissors. Cut through both layers of the shirt. Discard the top part with the arms.
Turn the shirt vertically. One of the sides of the shirt will be close to you. Start cutting the shirt 1 inch from the open side. Cut up toward the opposite end. Stop cutting about 1 inch from the top.
Cut again 1 inch over from the beginning of the cut you just made. Cut up toward the opposite end and stop about one inch from the top. Continue to make these cuts until you reach the end of the shirt. The result will look similar to a grass skirt.
Unfold the top of the shirt, the area you did not cut. You will see about 2 inches of uncut material. The beginning of your cuts will be above and below the uncut material.
Locate the first cut above the uncut material. Cut from where it begins to the edge of the shirt. Follow the strip of material you just cut with your hand until you reach the uncut portion. Cut across to the other side. Follow the material you just cut until it returns to the uncut portion. Keep cutting across until you reach the end. You will have a long strip of material. Roll the strip into a ball and set aside.
Continue cutting strips out of the shirts until you have at least three balls of strips. The more strips you cut, the larger the rug.
Tie together the ends of three of the balls of material. Braid the strips until you reach the end of the material. Tie the end of a new ball of material to the end of the material you braided. Keep braiding, and adding new material, until all of the strips are used.
Thread the sewing needle with crochet cotton or yarn. Take the end of the braid and begin to coil it into a circle. Coil so that the braid is flat and the sides of the braid are touching.
Tack the braid every inch to hold it together. Put the needle through one coil of braid and out of the braid right next to it. Do not pull the yarn all the way through, but leave at least 1 inch remaining. Put the needle back through the first braid and out the second again. Tie the two ends with a double knot and cut the yarn near the knot. Continue coiling the rug and tacking it together every inch.