Those funky looking ones, like a figure 8? If so, I've never been able to reuse them once installed, one shot usage. They are a pain to install, must be a trick to installing them....
I bought this style of pliers for the stock 1/8" cir-clips and they work well. Here are the ones for 4mm clips...either should work. Tips are the correct size for the funky clips... I bought the 45 angle ones...