Things You'll Need
Liquid dish soap
If your beanie is too big, whether because of a knitting or crocheting miscalculation or because it stretched, you can shrink it back to size with hot water. If your beanie is 100-percent cotton, you can shrink it with a trip through the washer and dryer, but if it's 100-percent wool, you will need to felt the fibers. Felting is the result of exposing animal fibers to heat and agitation, then shocking them in cold water.
Fill a large cooking pot half full of water and add five drops of liquid dish soap.
Put the pot on the stove and bring the water to a boil.
Reduce the heat to a simmer and drop the beanie in the water.
Stir the water with a wooden spoon, agitating the beanie. Put on a pair of rubber gloves to protect your hands and lift the beanie out of the water. Plunge the beanie into a sink full of cold water and scrub the fibers together. Add a drop of dish soap directly onto the wool to make suds, which will make scrubbing easier. You will see the fibers start to felt together — the stitches will become harder to see, and the yarn will start to look fuzzy.
Return the beanie to the hot water and stir it some more. Repeat steps 4 and 5 until the beanie has shrunk to your satisfaction.