Registry is a uniquely Windows OS feature, Mac's do not use registry.
For Cookies make sure all browsers are fully exited. This mean not just closing the window, like you do in Windows, but using CMD+Q while the browser is in the foreground to quit.
I am a new mac user also but have been using ccleaner for years with windows. Along with VGA free it was all I ever needed. CC was working fine for a long time on my mac till one day it just stalled wouldn't do squat. I tried the check by check method and found two places that were hanging. First one was trash, second was chrome cookies. Also after going check by check I got the "oh snap" from Chrome and Safari got stuck in a loop of crashing and trying to re-open. A reboot solved that and all seems to be working fine now. I'm a little scared to try and wipe the free space.