Which tool is NOT commonly used for nail enhancements?

The tool that is not commonly used for nail enhancements is an exfoliating scrub. Exfoliating scrubs are typically designed for skin care, focusing on removing dead skin cells and improving skin texture. They are used in manicure or pedicure treatments to prepare the skin but do not contribute to the actual enhancement of nails, which is the primary focus of the other tools mentioned.

In contrast, builder gel, nail tips, and acrylic powder are all specifically designed to enhance the nails. Builder gel is used to create a more durable and sculpted nail surface, nail tips are added to extend the length of natural nails before applying products, and acrylic powder is mixed with a liquid to create a strong, protective layer on the nails. These tools are all integral parts of the nail enhancement process, which is why they are not comparable to an exfoliating scrub regarding enhancing nails.