jhsu802701: I've been using the leftover jars as food storage containers, but I've realized that there's another use for them. Drill a hole through the lid to provide an inflow path for a small computer fan to be attached to the lid. Drill a 1-inch hole in each of the sides and the bottom. Cut up one of those cheap face masks to cover each hole, and use tape to form an … [Read more...] about Square plastic jar design