I don't buy anything new that is dry clean only. Anything secondhand with a dry clean label goes in the washer. I've only ever ruined one item. It was a dress I bought new and I think it was acetate. I washed it in the bathtub and literally watched it shrink right before my eyes. I've washed lots of rayon without trouble.
I've washed suede work gloves in the washer. It was either that or throw them away. I hung them to dry and they were a little stiffer but clean. I put running shoes in the washer and hang them to dry. I've put polyester (I think) purses in the wash and they were fine.