How to Make a DIY Precision Oil Dropper Bottle Cap. This video demonstrates a clever life hack to transform an ordinary plastic bottle cap into a precision dropper. This technique is perfect for applying lubricants or liquids to tight spots without making a mess. Step-by-Step Instructions: * Heating: Gently heat the center of the plastic bottle cap with a lighter until the plastic becomes soft and pliable. * Shaping: Press a toothpick from the inside of the cap outward through the softened spot