How did Easy E show Adam a cheaper way to do his laundry?

He did the laundry while using the shower:

The freedom to shower as long as I wanted on Saturday night gave me an opportunity to do laundry for the first time, a system that the ever-so prudent Easy E had introduced me to the night before. Instead of spending several dollars per load plus the cost of detergent, he showed me how I could use my regular bar of soap to clean my clothes in the shower and where I could hang them each night so that they would be dry by the time I woke up the next morning.