Lay bubble wrap onto a flat, waterproof surface with bubble side facing up.
Lay yarn back and forth across top of bubble wrap in a continuous strand of spaced vertical lines to cover an area about 8 x 30 in. (20.5 x 76 cm) (This is larger than finished scarf since shrinking will occur during felting process). Lay yarn in opposite direction to form a second layer of strands. Continue layering yarn in alternating directions until about half the yarn has been used.
Fill spray bottle with hot water, add a small amount of dish soap. Spray yarn evenly with hot soapy water, being careful not to soak. Roll up bubble wrap tightly to encase yarn. Wearing rubber gloves, begin to roll bubble wrap back and forth vigorously, pressing firmly, for about 5 minutes.
Unroll bubble wrap, and spray yarn again lightly. Roll up bubble wrap in opposite direction, then continue rolling vigorously for another 5 minutes.
Unroll wrap and check felting progress. Yarn strands should have begun to felt together.
Continue to roll, changing direction and checking felting progress every few minutes.
When yarn is felted to your satisfaction, rinse piece very gently with cool water. Roll felted piece very gently between 2 towels to remove water, do not wring or twist. Lay piece flat to dry.