Swap Option: A Hodgepodge
How to organize: Since anything and everything is allowed, you want to keep the swap from looking like a junk sale. Designate and label areas of the room as different departments, as in a store (housewares, gardening). Use bins to keep it tidy.
What to consider: People can go overboard when cleaning out their garages, so think about how much space you can dedicate to the swap. You may want to suggest that guests limit the number of items or their size (in other words, nothing bigger than a bread box).