Wool is fine with washing in cold water....ever see those sheep in Scotland? They are constantly getting washed in cold water. All the time.
Hot water makes the fibers swell too fast and it is agitation that shrinks wool (the fibers mat). Of course if you got a sweater that is way too big, you now know what to do.
Cold water. No or little agitation. NO WRINGING. Rinse well. Dry flat.
I live in wool. I spent years in Scotland in the damp learned that Wool Is Your Friend. Even in the summer. Then it is fine fine merino wool. Unless it is really too hot, then I'm probably nude in the pond. Or wearing woven linen, wrinkled or not (never t-shirts, that jersey knit traps the heat too much.)
The only thing that I ever consider taking to the drycleaners is a suit, cause of all the interfacings and pads and such. But, that only happens about once every three to five years because I FANATICALLY brush my clothes after wearing and before wearing with REAL bristle brushes and air them after wearing and do spot cleaning if necessary, so positively YEARS go by without drycleaning.
I have a great book called Taking Care of Clothes. Cheap trade paperback I got fourteen years ago. I'll get the author name and publisher and post it here. Maybe it is still in print.
I find that synthetics need drycleaning more than all naturals (wool, silk, cotton, linen, etc.). And they hold oily stains much, much worse. And I feel NASTY in synthetics.
edited to add: I just read the pendleton blanket question. I wouldn't wash it in a machine. Too much agitation. I'd do it inthe bathtub. To rinse, several changes of water, spray with the hand held if you have one. Or wash outdoors on a rack in the shade and hit it with the garden hose to rinse.
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