Thanks very much everyone. All of your replies helped.
I'm actually asking cause my friend was suspected of a crime I can't disclose and the forensic expert found nothing on his PC, but he did found CCleaner installed and kinda implied my friend is possibly guilty cause he had an "anti-forensics" software installed.
The friend was only using CCleaner exclusively to clean temp & junk files on C: cause he was lacking space on C: drive after years of windows updates shrunk the free space on it to a few Gb's. He didn't even clear his browsing history or the downloads folder with it. I was asking to confirm if I had the wrong impression of what CCleaner does, but you guys reassured me, thanks.
P.S. love the car, windows & paper shredder examples.