best system cleaner for mac

[paul001]

I am a PC user and I love the nCleaner system cleaner. It works like a charm. My father's a Mac user and is in need of a good cleaner for his system. What do you all recommend?
Thanks

[socrates]

I've never found a need for one on my mac, nor have I ever had a mac user ever need one (I used to work as a tech at apple and am now an apple systems admin). 

Are you sure this is what he needs, and that his problems are related to something else?

[paulabee]

I was thinking that maybe that is what I needed. I am not a computer pro. I bought a mac last year, have always had pc. I like it but it has begun to freeze up sometimes, respond slowly, it acts like a pc full of junk. I don't know how to compress the files, defrag, clean up or anything...i just here that you never have to. So I'm asking how do I know what's wrong with it?

[BC_Programmer]

I'm no apple expert, but you could try reinstalling the OS from your system disk, after backing up your valuable data.