How often is the ECCC queue cleared?
Here is an excerpt from the call for papers that explains the procedure:

As soon as a submission arrives, several board members with expertise in its declared area are notified, and once a week all board members are sent the list of pending submissions. Board members may screen a submission at their own discretion, and make the decision whether or not to accept it. An accepted submission is posted as a report immediately. A submission is automatically rejected after two months if no board member accepted it.

The call for papers also lists the members of the board.