Me too, I always hand wash my finished works, (and that's necessary !) without any trouble. I use DMC floss and danish threads, which are more fragile, but they are not affected by a light washing.
Hand wash always, never had a problem and always turns out great. Just in a bowl or the sink with some dish detergent, soak in warm water for 10mins, then rinse under cold until no bubbles left. Gently ring out as much water as possible, then iron the reverse side through a bath towel, works great everytime.