Both baking soda and loofahs are physical exfoliants. They remove dead skin cells by friction. Chemical exfoliants take a different approach. They penetrate the skin and chemically dissolve the bonds holding skin cells together, allowing the older, dead cells to be washed away. It's a less abrasive method of exfoliation that can benefit most skin types.
One popular chemical exfoliant is BHA, or beta-hydroxy acid. BHA, in the form of salicylic acid, is ideal for acne-prone, blackhead-prone, or otherwise oily, blemished skin. Unlike other chemical exfoliants, salicylic acid is oil-soluble. Since it can dissolve into the oil inside pores, it can remove the dead skin cells that are helping to clog the pores and cause blackheads or "breakouts." BHA can be better for acne-prone skin than a scrub, since friction can make acne worse.
Up next, a chemical exfoliant with wider range.