Keratolytic means

It is customary to call medicinal substances that promote softening and rejection of the stratum corneum. They are used in the treatment of diseases accompanied by pronounced hyperkeratosis, the formation of dense powerful crusts, as well as to remove nails when they are affected by pathogenic fungi (see Onychomycosis).
Keratolytic agents include salicylic and lactic acids, alkalis, in particular green (potassium) soap, resorcinol. The most commonly used is salicylic acid. 2-5% of the ointment causes exfoliation of the scales, and 10% or more of the strong ointments, as well as the lacquer or plaster, macerates (like alkalis) the stratum corneum, which is therefore easily scraped or flaked off in large layers. To strengthen the keratolytic action, lactic acid is added. Resorcinol, used in the form of 5-10% ointment, has a different effect. It dries out the stratum corneum, resulting in the latter becoming a parchment and easily removed from the skin with a thin film.