What type of preparation temporarily removes superfluous hair by dissolving it at the skin line?

The correct answer is depilatories. These products are specifically formulated to remove hair by chemically dissolving it at the skin line. Depilatories work by breaking down the protein structure of the hair, effectively softening and releasing it from the skin. This method is often favored for its ease of use and speed, allowing for quick hair removal at home or in a salon setting.

In contrast, waxing involves the application of a sticky substance to remove hair from the root, providing longer-lasting results, but it does not dissolve hair at the skin line. Shaving cuts hair at the surface level and does not provide the same results as depilatories, as it does not dissolve hair at its base. Threading is a method that removes hair by pulling it out from the follicle with a thread, which is precise but also does not involve dissolving hair. Therefore, when it comes to the temporary removal of hair through dissolution at the skin line, depilatories are the accurate choice.