Before applying any of the components in the POR-15 floorpan resto kit, thoroughly clean the area to be repaired. Removing built-up corrosion and other debris not only yields a better surface for the POR-15 to adhere to, it also gives you a better chance to assess the true extent of the damage. In our case, it turned out a lot of what we thought was rust was actually just residue from the rotted carpet padding. The actual damaged area was much smaller than we first thought, which only reinforced our confidence in using the floorpan repair kit instead of cutting out the affected area.