I say go either way....I am in a strip swap and we are putting them in a plastic bag before mailing and marking each bag with our name, address, site nickname, "washed" or "not washed" and then mailing it off. Party handling the swap will mail washed to senders who send washed and non-washed to non-washed senders. That way everyone is happy.....ain't life all about being HAPPY!!!!!