Use 35 mm film canisters to keep household extension cords neatly bundled. Start by cutting the bottom out of a canister. Loop cord into a one-foot circle, squeeze it flat, and slip it through the open-ended container.
This collar will keep the cord cinched, and is easier to remove than a twist-tie. Just slide the film can off when you want to use the cord. If cords are a little too thick, try slitting the canister down the side and "clipping" it onto the extension cord.
