Shrink and felt sweaters: Wash the sweaters in a washing machine with plenty of detergent and hot water. Some sweaters may require several washings to get the best result. Dry in clothes dryer on high heat.
Use a sweater comb to remove pills and soften felted sweaters.
Measure sides of foam cube and cut a square from mat board or cardboard to match dimensions. Use this template to cut 6 squares from various felted sweaters with a rotary cutter.
Sew five squares together into a cube with a blanket stitch, leaving off the sixth side.
Cut into foam cube with utility knife, and stuff caged bell cat toy into center. Stuff foam cube into stitched squares. Attach last square with a blanket stitch, securing foam inside.