Felting
There are two common felting methods; Wet Felting and Needle Felting.
When wet felting, hot water (sometimes with added soap), is sprayed onto layers of wool, while repeated agitation and compression causes the fibres of the wool to hook and weave together into a single piece of fabric. Only certain types of fibre can be wet felted well. Most types of animal fibres, such as those taken from alpaca or sheep (lambswool, shetland), can be put through the wet felting process. You can also use mohair, cashmere (goat) and angora (rabbit). Avoid yarns that are machine washable as they have been treated and will not felt.
With needle felting, this method doesn’t require any water. You use a special needle that has notches along its shaft, these catch the wool fibres and tangle them with other fibres to produce the felt.