Originally Posted by Little Cletus
Turn the garment inside out and put it inside a mesh washing bag. Wash it in a machine on the cold water gentle cycle which is really mostly soaking it with only a little agitation. Use some high quality detergent and no more than 1 oz like a shotglass. Take it out and dry flat. I hang my things on hangers to dry but the hangers are wide and have wide ends and don't leave a mark on the garment.
The problem with hand washing is that it's even harder on the garment then machine washing and that you have to squeeze the water out which may effect the shape while the machine on gentle cycle gently spins it out. A dryer sweater when it comes out can be hung on a hanger but a hand washed one has more water in it and will stretch.
I agree with this.
The problem with wool (and perhaps, also, cashmere, I'm not sure?) is that the fibres are covered in microscopic hooks, so agitation and squeezing, especially when wet, will make these hooks snag on each other (hence the matting and shrinking).
Fortunately, I have a newish machine, with a very good wool cycle and things come out even better, after that, than they do after a cold handwash (even though I'm very gentle, promise!).
They look brand new, or even better than brand new (i.e. slightly fuller).
For pure wool and cashmere, I would also tend to turn down the heat from the preset 40 degrees, to 30 degrees (although, I'm not sure if it's strictly necessary?).
If you have an older machine, though, or one without a very specialised wool cycle, I'd stick with the very gentle cold handwash in Woolite for Colors and then, after rinsing, rather than squeezing much at all, maybe just put it in the machine to drain (not spin), once you've finished (again, if you have that option, obviously)?