Will definitely be doing that! Smell was one of my concerns!Several benefits! (1) charcoal is great for absorbing toxins and other harmful substances in the substrate. This is especially useful for keeping your plants and microfauna happy and healthy! (2) charcoal reduces odor from things like decomposition, mold, and whatnot. (3) it's also good for drainage. I buy the chunky horticultural charcoal from local plant nurseries.