I rarely wash knits in my washing machine, even though it has a dedicated wool cycle. For dry clean only items, I do get them dry cleaned. With these knits, I generally wear a t-shirt under the knit, to avoid excessive cleaning.
For washable knits, I hand wash with a liquid detergent (personally I use a wool wash product) and rinse in cool water. Rather than wring out the water, I gently squeeze the water out and then place the knit on a clean towel, at one end. I then fold the towel over, so it sandwiches the sweater and then I stamp my feet over the towel, which draws all of the excess water out of the sweater. I then air dry the sweater by laying it over a laundry dryer, so that it dries flat. Whilst this is all a bit of a bother, it very gently cleans the sweater and I have never ruined a sweater cleaning it with this method. Never hang a wet sweater to dry, because that can result in excessive stretching or the sweater becoming misshapen.
