1. Brew your morning pot of coffee
2. Fill your filthy peanut butter jar full of hot water
3. Drink your pot of coffee in the same manner you would any normal day
4. When you're done, refill your coffee maker with water and brew that.
5. Empty the filthy peanut butter jar of the hot (now lukewarm) water
6. Pour the second generation coffee (piping hot) into the filthy peanut butter jar
7. Watch in amazement as the peanut butter melts away revealing a pristine peanut butter jar

Coffee: It's a delightful beverage and a highly acidic industrial cleanser!