How to remove items from publishing using a Tridion Resolver?

I am trying to do implement a custom resolver for a component as described here by Chris: http://www.tridiondeveloper.com/the-story-of-sdl-tridion-2011-custom-resolver-and-the-allowwriteoperationsintemplates-attribute

I want to remove some of the binaries (mostly pdf's) used in component and prevent them from publishing. I am able to get the list of used items using item.GetListUsedItems method. How do I remove them?

using : tridion 2009