What do I do with returned direct mail?

[Noah McPherson]

I see some forum posts about returned letters from direct mailing campaigns, but not specifically the answers I'm looking for. (I'm sure this will help other beginners in direct mail marketing too) Anyways, we sent out direct mail, and we got a pile of returned letters. My question is, should we skip trace everyone we got returned letters from? The reason I ask is because some of the people we got returned mail from don't show up as the owner any longer on the tax assessor website. We don't need to track down the owner of the subject property if it's a new owner, right? Thanks!