you can't re-use those clips. You can get a tool that crimps new clips on, don't think it's VW only, pretty sure various tool places will sell them. But to be honest, they are a pain in the arse trying to use pliers will just fuck them up and you'll not get a seal. What pipes are you planning on using them on? If the fuel pipe then just get some proper fuel pipe clips from any motor factors they are much better and re-usable! Jubilee clips are no good for fuel pipes as you have to overtighten them to get a proper seal which can knacker the pipe.