I am new to skincare and am looking to introduce exfoliation into my oily skin routine. On Yesstyle, I'm mostly seeing exfoliating toners such as Cosrx AHA/BHA. Is that equivalent to an exfoliating cleanser that I could use once or twice a week? It seems odd to me that exfoliation removes dead skin and sebum, yet it would be left on the skin as a toner. Please help this noob to understand the difference.