When it's time to replace your shower curtain, save the old one and use it around the house. The waterproof liner works great as a drop cloth when you're painting around the house or as protection for outdoor plants in the cold winter months. And when you do replace your shower curtain, be sure to look for one that is free of polyvinyl chloride. PVC releases chemicals into the air and is very difficult to recycle. A good option is nylon, which is waterproof and does not need a liner.