Medium-grit abrasives (150 to 180 grit) are used to:

Medium-grit abrasives, falling in the range of 150 to 180 grit, are specifically designed to smooth and refine surfaces during nail care. They serve a critical purpose in preparing the nail surface for further treatment, ensuring that the nails are even and free of major imperfections. When using medium-grit abrasives, professionals can effectively eliminate roughness and create a more refined finish, which is essential for achieving a polished look.

The choice of medium grit is ideal because it's effective enough to refine surfaces without being too coarse, which could cause damage or split the nails. This balance allows for the preparation of both artificial and natural nails before applying polish or other finishing products, enhancing the overall aesthetic and health of the nails.

In contrast, other options pertain to different functions. For instance, while removing calluses typically requires a coarser abrasive, polishing nails usually involves finer grits to achieve a shiny finish. Shaping nails can be done with various grits depending on the desired outcome, but medium grit is primarily focused on smoothing rather than shaping. Thus, using medium-grit abrasives to smooth and refine surfaces aligns perfectly with standard nail care practices in cosmetology.