I pulled one of the knobs on my BB. I ‘think’ a pair of bent needle nose pliers would be able to fit in
to the sides of the nut. If the plier tips are a bit to big, take some off with a file so they fit in the recess. It needs to be bent because the ‘V’ of straight needle nose pliers would hit the knob shaft and not get into the nut recess. If the link below doesn’t work, just search Amazon for …’bent needle nose pliers’.