Solid shampoo bars are gaining popularity lately for a couple of reasons: the desire for alternatives to products packaged in plastic and people looking to reduce toxic chemicals in their personal care products . Never heard of shampoo bars? Or is it hard to wrap your mind around how to use solid soap on hair? Read on! Here's a Quick Rundown of How To Use Them: Wet your hair - right to the roots! Rub the bar along your hair from head to hair ends like you're brushing it, l