Washing wool clothes is the one and only thing why knitted garments annoy me. I am super-not-into-hand-washing my clothes (especially after I did it every day for 6 months). You might get away with using washing machine, but you know the horror stories where people shrunk their lovely cardigan so much that it now perfectly fits to a toddler:D
My Mom, as an avid knitter, has taught me trough the years how to take care of my knitted garments. She always frowns upon me when I’m sometimes being lazy and just toss my knitted socks in a washing machine.