Fox News host Brit Hume is discussing the Clinton “conspiracy theories” tonight.  He identifies the “Cleaner” as long time Democrat strategist Brady Williamson who has been part of the debate negotiating team for decades.  Mystery solved.
Here’s a ‘slightly’ better video synopsis of the controversy:

Takeaways:
• Three or four individuals are removing items from the Clinton lectern after debate.
• There are at least 7 trips to the lectern (four by Brady Williamson) After debate.
• One of the trips (not Willamson ) removes a cup of water. The other six ?
• During each removal there is a person watching over.
• The last time Brady Williamson visits the lectern he is most likely putting something back, it appears to be a brown box, not necessarily taking something out.