Yes, folding knives can be used to cut plastic bottles. Plastic bottles are relatively soft and can be easily cut with a sharp blade. Folding knives are designed with a folding blade that can be safely stored and carried, making them handy for various tasks, including cutting through plastic materials.However, its important to exercise caution and follow proper safety practices when using any type of knife. Make sure the knife is sharp, use controlled and deliberate cutting motions, and pay attention to your surroundings to avoid any accidents or injuries. Additionally, be aware of the potential risks associated with cutting plastic bottles, such as sharp edges or the release of liquids.