Are you eliminating 3-4 times a day? I'm on day 3, and like last time, am passing mainly water and lemon bits. I don't expect to see the darker gunk until day 7-8 or 9. If I don't see it then, I'll keep on going.
My guess is you haven't passed much you're body is still releasing. Many would recommend you do a SWF (Salt-Water-Flush) if you are not getting maximum results. It's worth a try if you can tolerate it. If you stop at day 6 you can't be sure you're reaping the benefits of the cleanse. If you've come this far then I'd encourage you to push onwards to day 10!