Is it a bad idea to use a normal bath sponge to exfoliate your face?

Well maybe if it works for you... maybe you have thicker skin, but ya its usually reserved for the body which has thicker skin. Facial skin is usually thinner and you can break small capillaries, those small blood veins usually around the nose if you scrub too hard and you will have redder skin which you dont want.. so if u must just exfoliate gently with it. Too rough and you can ruin the delicate facial skin.