I discovered these about 12 years ago and since then, one has always been a mainstay of my bathroom accessories.
This is a very light, very gentle exfoliating sponge which does wonders for my skin when I use it once or twice a week. Using my regular facial cleanser (e.g. Clinique Facial Soap) I apply as usual before using the sponge to gently exfoliate my skin. I use gentle, circular motions concentrating on the more stubborn areas like the middle of my forehead, jawline, sides of nose and chin, where I often feel it needs a bit more effort. For someone with sensitive skin, this has never once left my face feeling sore - it sloughs away the dead skin nicely and leaves my skin looking and feeling very soft and 'new'.
These only cost about 1.90GBP from Boots and more often than not they are on 3 for 2 meaning you can stock up. If you're looking to start exfoliating but aren't sure where to start (or don't want to spend money on expensive exfoliating creams/lotions) then I would highly recommend giving this a try with your regular cleanser. It certainly works for me!