1. First cut sweater, interfacing, batting, and lining into two pieces. Iron the interfacing onto the wrong side of your sweater by pressing and lifting iron across the sweater so the shape does not stretch and get distorted.
2. Stack your cut pieces. The sweater pieces should have right sides touching, and be sandwiched in between the batting. Sew both sides and the bottom with a 1/2 inch at the edges of the fabric.
3. Box the corners by laying the side edges against the bottom edge. Sew it across the corner approx 2 1/2 inches from the point. Turn your bag right side out. Cut 4 pieces of ribbon into 3 -inch lengths. Feed the ribbon through the handle openings and pin them upside down onto the right side, top edge, of the purse.
4. Arrange lining pieces so that right sides are touching. Sew both sides and bottom, but leave an opening at the bottom with a 1/2 inch at the edges. By keeping the sweater right side out and the lining wrong side facing out, slide the lining over the sweater. Purse handles are between the layers. Line the edges and pin. Sew all the way around the opening with a 1/2 inch at the edges.
5. Pull the sweater through the opening at the bottom of the lining. Sew the opening at the bottom of the lining closed. Tuck the lining into the bag. Press the top edge so the lining lays flat inside the bag. Enjoy new sweater bag!