If you are going to delete the "CenterOfMass" prop, I highly recommend that you also delete the corresponding hidden "GoalCenterOfMass" prop as well. If you do this in a text editor, or use a cr2 editor such as CR2Builder, as long as both are removed, then it's completely safe to do so. But remember that these props occur in three places in the cr2, and you must delete all three parts of the pair of props. As to trying to delete them from within the Poser interface, I don't know, but it sounds risky.

Quote - But isn't it strange when a hair prop, from the hair prop library, has 4 CenterOfMasses?
How do non-figures aquire CenterOfMasses? scratches head

Are you sure they are props? Some things in the props folders are actually figures, even though they are filed under props, and have a pp2 (or ppz) file extension.