what is a good too, that will take out a circlip will ease and not damage my piston?

 

instead of too, its suposed to say tool

 

Umm The best thing to use is circlip pliers, They have pointed ends and usually u can change the pivot point so u can undo internal or external cir clips, They are cheap and you can buy them from most hardware places, Or you can just use a small screw driver, or grind some points on an old pair of needle nose pliers. Good luck man
(umm just reread your post and saw the piston part those clips dont have holes in them usually so I just use a very small screwdriver for those make sure you are careful and dont lose it or worse drop it down into the engine stuff the hole with rags )