Lead-Safe Remodeling
To make an effective airlock — one that lets people in without letting dust out — use two layers of 6-mil plastic. The first layer should be a few inches longer than the doorway and about a foot wider (so there's plenty of slack in the middle). After duct-taping all sides of the plastic, cut a slit down the middle, stopping 6 inches short of the top and bottom (reinforce the ends of the slit with duct tape). Place the second layer of plastic over the first one and tape it to the top of the door.