RemoveMovieClip Problem

I defined my duplicated movie clip under a variable

var duped:MovieClip = duplicateMovieClip(_root.MC, "MC"+_root.getNextHighestDepth, _root.getNextHighestDepth);

But I can’t remove the movieclip when I use

removeMovieClip(_root.duped);

Could someone help?

By the way I didn’t use a for loop because I want to duplicate one MC every second but have more than one movieclip on the screen.