What method of hair removal involves using a heated substance applied to the skin?

The method of hair removal that involves using a heated substance applied to the skin is waxing. In waxing, a warm wax is spread over the areas of unwanted hair. Once it cools slightly, a cloth or paper strip is pressed onto the wax and then quickly pulled away, taking the hair out from the root. This method is effective for removing larger areas of hair at once and leaves the skin smooth for an extended period since it removes hair from the follicle.

Tweezing specifically targets individual hairs using a tool called tweezers, which does not involve any heated substances. Shaving, on the other hand, uses a razor to cut hair at the skin's surface without any application of heat, and chemical depilation refers to the use of products designed to dissolve hair at the skin level, typically without heat. Thus, waxing stands out as the correct method involving a heated substance applied to the skin for hair removal.