I know that many people know that you can sell bracer piece that you purchased with Emblem of Valor but some people may not know this yet.
In patch 3.1.0, Heroic Ulduar will use new emblem, Emblem of Conquest. So if you're collecting Emblem of Valor and planning to use it to buy 25 man level of Ulduar gear, you can't. If you have something you need with Emblem of Valor, you'd better spend it now. If you don't have anything you need from Emblem of Valor anymore, you should sell it as bracers. You should do this before more people started to know about Emblem of Conquest too, or the price will drop dramatically.