Piktor over on .org has come to the conclusion that since there are photos showing two doors in the cottage - the doors to the small bathroom and Meredith's bedroom - with blood on their interior faces and/or edges, but no blood on their exterior faces (i.e. those facing the hallway when the door is shut), this somehow proves that there was a post-crime clean-up. Furthermore, the "argument" states that the "clean-up artist" deliberately cleaned the exterior faces in order to make the doors seem normal when viewed from the hallway if they were closed.
Unfortunately, Piktor has got this argument completely wrong. His/her conclusions are the result of ignorance and a failure to look at the situation properly (or objectively). Here's why:
Both the doors in question open inwards - that is to say they open in towards the bathroom and bedroom respectively. Therefore if either door is pushed to, provided it is not latched shut, if one wanted to pass from the hallway into either room one would be pushing the door open. If the door was not latched shut, then one wouldn't even need to use hands to push the door open: a shoulder, elbow, chest or knee would easily suffice.
But conversely, if one were inside either of these rooms with the door pushed to, then in order to exit the room one would need to pull the door open. And in order to do so, one would almost always need to use hands to grasp either the interior door handle or the edge of the door, in order to get the necessary purchase to pull on the door.
So it takes no more than a basic amount of intelligence and knowledge of the layout of the cottage, coupled with objective reasoning, to figure out why there might be blood on the interior face and edge of Meredith's bedroom door, and on the edge of the small bathroom door, but no blood on the exterior face of either door. It's nothing whatsoever to do with a "clean-up". It's to do with the dynamics of the crime and basic physics.
If Guede alone stabbed and assaulted Meredith inside her bedroom (as I and many others believe), then it's highly possible that the bedroom door was pushed shut at some point in the event - either during the struggle in the relatively small room, or because Guede might have pushed the door shut after pursuing Meredith into her room. So, if that's the case, then after the murder Guede would have been confronted by a pushed-closed door, and he would have certainly had blood on his hands. Therefore, in order to exit the room (so that he could clean blood from himself and get towels), he would have had to use his bloody hands to pull the bedroom door open inwards. That's how and when blood would have been deposited on the inner face and the edge of Meredith's door. He wouldn't have bothered to pull the door shut again behind him at this stage, so no blood would have been deposited on the exterior face of the bedroom door.
Perhaps the bathroom door was pulled shut, or perhaps it was wide open. Either way, then provided it wasn't latched shut, Guede would not have needed to make any manual contact with the door in order to open it: if it were pulled to he could have used his shoulder or a blood-free knee to nudge the door open. So no blood would have been deposited on the exterior surface of the bathroom door. It's then possible that Guede either brushed against the edge of the door as he entered the small bathroom, or that he pushed the door shut by touching the edge. Either way, this would account for the blood drip on the edge of the bathroom door. Once inside the bathroom, Guede would have washed his trousers (depositing the blood-water partial print on the bathmat in the process) and his hands/arms - most likely in the shower. After washing, he would have grabbed two large towels and would have dried off his trousers, hands and arms.
From this point onwards, therefore, Guede would have had essentially no blood on his hands. He would then have left the small bathroom and returned to Meredith's room. Any handling of either door from this point on would not have resulted in any blood deposit on any surface of either door. So when Guede finally left Meredith's room and used her key to lock the door, he would have been able to pull the door shut using the handle, without any blood deposit on the door handle whatsoever. Furthermore, even if there were microscopic dilute traces of blood (that might have remained on Guede's hands) on the exterior handle of Meredith's door, this evidence would have been obliterated by the subsequent repeated handling of the door handle the following day by Knox, Sollecito and the postal police.
So this is why there was blood on the interior face and edge of Meredith's bedroom door, and the edge of the small bathroom door, yet no blood on the exterior face of either door. There was no clean-up of either door. There was no attempt to make the exterior surface of either door seem "normal" as part of some fiendish post-murder plan by Knox/Sollecito. In addition, of course, luminol tests would almost certainly have revealed any attempt to wipe down the exterior faces of either of these doors. Neither exterior face was cleaned of blood after the murder. The exterior faces of both doors were blood-free due to a combination of the likely dynamics of the murder and the direction in which both doors opened. It's really very simple indeed. Unless, of course, you employ poor reasoning, inherent bias and simple ignorance to convince yourself that this was evidence of a devious post-crime clean-up plan by Knox and Sollecito.....