Collectors on the Mission Map

Collectors can be found both inside and outside towns and outposts. In Nightfall, you can find a Collector outside a town or outpost by checking your Mission Map. (Press "U" to open or close it.) Each Collector on that map has a label showing what he or she collects.

Special Collectors who accept trophy items work the same way. For instance, if you want to trade in Battle Commendations, look for a Collector on your Mission Map with the name of that trophy item next to it. http://www.guildwars.com/gameplay/gwnfeatures/collectors.php