I was wondering if anyone has tried using rebrickable with a bulk used lot? Although it would be a lot of work, I have thought of inventorying my bulk lots in rebrickable to see what I have complete or near complete. The lot I am working on now had two retired batman sets that I may have put some of its needed bricks with bigger sets that go for the same or less money. Granted I'm still new at this and did not recognize their value.

You would have better luck finding rare or printed/stickered pieces to find out what sets you have in a bulk lot.  Once you figure out what sets you may have based on those, then use a Brickset or Bricklink to inventory and see what you need.  That's the route I take at least.

Yeah. I have been using the mini figs as guidance. I saw that I had two batman figures but i didn't recognize the Killer Croc (head was missing) or Harley Quinn to know what sets I had. I didn't research them till after the Star Wars sets I found we're complete and sold. Then I saw what they were worth and had to BL some parts. It might have been useful to know the percentages of completeness of my sets first. But maybe the time it takes is not really worth it.

What huskers said....the work to inventory would drive you nuts and take hundreds of hours.

Now if you had a machine that could scan the pieces, identify them, determine color and do it quickly and accurately that would be another story. I think it would be possible to build something like that in theory.

Just an interesting concept really...