Several of the profiles in this category are not ready to be there. Some have birth and death dates (in some cases, these are pre-1700), others have family connections, and still others have profile managers.
I just did a bad thing by recycling one of these profiles that probably should not have been in the Recycle category. My bad was not noticing that the profile had a child connected. There was some kind of system glitch when I tried to disconnect the child - I did it 3 times and all three show up in the changes, but the child was still hanging on. About a half hour later (after my post about this and some discussion) the connection suddenly disappeared.
I'd like to suggest that a profile have no dates, no connections, and be an orphan when it is placed in the Recycle Unknown's category to avoid the chance of potential errors in the future.
Edited to add:
I just noticed one that has no data and no connections but this one has a profile manager and the template with how many degrees away from AJ it is!!!