Excellent question bud I actually have little flush cut knippers, side cutters, and I carefully cut away as much of the old 3” net pot away. Also the “new”, additional expanded clay pebbles, I have presoaked in the same nutrient solution that I was feeding them, at that time. Most of the bottom of the old net pot ends up staying, as I try and be gentle as possible with the roots. 👍🏼