Remember, when scanning, what the camera does not see, it does not scan. If you are just exporting a scan to print, you are doing it wrong. You need to FILL the model first, then do cleanup.
I use Meshmixer to do the cleanup after filling the model in skanect. after that, i reload the edit_me.ply for recoloring
in meshmixer there is also a hollow feature that you can use if needed. i tend to skip that and use the hollow feature in my slicing program for that.
Tobby