If you haven't already done the annual spring clean, there is no time to lose.
We know from your letters and experience that the best way to tackle the task is as a family social day -- but with military-like discipline. Organise and arm the troops with fluffy feather dusters, top-secret cleaning agents, buckets of elbow grease, rubbish bags, boxes and, most of all, a positive attitude as they march towards victory. Write down the Mission Impossible task for each trooper, and have them report back to HQ at regular intervals, rewarding them with lots of praise and a batch of home-made scones, or pikelets, if their efforts take the house to frontiers where no man or child has gone before.
Break the tasks down into small and simple steps -- a formal inspection of the guard, with regimented marching to music, is always a good way to begin. The battle plan should be to attack one room at a time. Work in pairs if need be and keep the communications short, sharp and snappy -- something like, Question: "What about this?" Answer: "Rubbish". Reply: "Ten-four roger that."
Start by rummaging through forgotten places. There may be lots of trash that you can turn into cash. Golf clubs (the old ones, not the new ones), unwanted household appliances (old TVs before 52in flat-screens became the minimum standard), furniture, books (the ones where pages turn rather than swipe) ... they can all be sold online, at a garage sale, swapped or given away to create space.
In the bathroom check the medicines for their use-by date. Destroy anything that's a bit dubious; it's dangerous having them lying around, especially if there are littlies in the household who think that colourful pills look like M&M's. Get the torch out and have a good look at the back of the bathroom cabinet.