Yes disk cleanup and system cleanup are great windows built in tools
I am a 70-year old geezer and not the brightest bulb on the tree; so, please bear with me.
When you say "disk cleanup" and "system cleanup" you give me the impression that there is another tool similar to disk cleanup called "system cleanup" which works only on cleaning system files? If so, could you please point me to it and give me a hint or two on its use (and safety). Naturally, I thank you in advance.