hot water- soap and agitation is what it takes-then into a hot dryer (i usually put the washer on hot...but i also turn on my tea kettle- and i add boiling water as the water starts to cool- and keep resetting the agitation dial to keep it washing- not draining and refilling- it takes sometimes a good hour of adding hot/boiling water and more agitation---when you think it is (done) cut a slice---the edges should not ravel- if they do- it needs more felting...and if it's a washable wool- it's not going to felt.
has to be 100% wool-
and some wools shrink less than others.
roving is (raw) wool fiber- usually purchased by weight- like by the ounce or by the pound- it is used for wet/hand felting and for needle felting.
you can purchase it from sheep-llama-alpaca farms- wool shops, some on line places.
wool is wonderful to work with- and Sue Spargo sure does some fun stuff! have fun with it.