What's on top, though, is just junk, and you need to clear that away first. You shovel it away, one story at a time, and you pitch the stuff that's obviously useless. Chances are, it's no good, and he'll send it back. Eventually, though, if you keep working at it, you'll get to some nice rich fertile stuff in there, and the editor will eat it right up. Of course, there's some variation.
Some people dig for years and never seem to reach anything worthwhile.
But if you don't start digging, you'll never know what's in there. So you need to actually write, not just look at the pile and imagine what might be in there. Pitching ideas is just adding to the pile. Writing is the only way to dig into it. Many writers use a daily quota, and it's a good way to get yourself started and instill some of the self-discipline a writer needs.