Boots don't work very well as smart props, in my experience. Since these ones cover thigh - shin - foot - toe groups, there would be some part of them that didn't bend properly no matter how you parented them. The method we've been through here has the advantage of preserving the grouping information (which Anim8or doesn't do), so that it's easy to make a conforming item with what's left. Anybody looking for a free solution should try John Wind's Compose, which can delete by group and / or material in the same way. It requires Java, but will work on Macs also.