Washing seeds?

This is kind of a weird question, but I was thinking about it the other day. Should I wash seeds (like flax seeds and such) that I buy from the store? I've never washed them before, but I don't think they come washed. If I did wash them though, it seems like they'd get all mushy.

Some seeds could be washed, I suppose. Its not much different from the rinsing you do when you sprout them. But washing flax seeds would make them gummy.