My copy of theEF 70-200mm f/2.8<span style="color: red;"]LIS II USM arrived last week, completely clean. But, if it had shown up with internal dust, I would not have left it alone. I suppose it would depend on how I bought it - if it was from a local brick-and-mortar shop, and they had another in stock, I'd exchange it. B&amp;H online (how I got mine) also handles exchanges very well. But otherwise, I'd just send it to Canon.