Digital BW, The Print

I just recieved my set of refillable carts for my C86 and sit and stare 
att the supplied tiny plugs. They don't really seem to be design to be 
removed, now do they? No collar to grip for example. Those see-through 
carts have a hole/well that is quite deep. So I'm thinking of 
re-engineering them but before I do I'd like to know if I'm right or 
just beeing my old negative self? No use to go to unnecessary trouble 
(and there's always the risk of botching the job to boot) if they 
actually _are_ repeatedly removable. Perhaps somebody has found exactly 
the right tool/technique for the removing?

henrik