Tasks After The Congress
Players love to clear up after tournaments - all they need is a little encouragement and a list or example of things that need doing.
One organiser beginning to clear equipment / rubbish can be just the catalyst to start this process - the organiser can then leave them to it, and just check that all is complete at the end.
Do not wait until most people have gone - tesuji works best whilst everyone is there - it is also quicker.