Ah yes, the clamps I refer to as the clamps from hell. All I have found on my older skis have been loose, but not quite loose enough to just fall off most of the time ... just tight enough to make you tempted to use more force than needed and break something.
2 methods shown have worked for me. One is to use (sharp) dykes and clip thru the top band. Other (I prefer) is to use flush-cutting dykes to lift the bent over locking tab then use that tab for leverage to lift the band up over the tab.
Hopefully the pics explain better.
good luck, and do not break anything.
Rod