Q: What is the best way to clean up Mac?

The outside or the inside?

If you mean the software, the best thing to do is not try to "clean up" any of it unless you have some specific problem that would benefit from that.

You don't need to do any routine maintenance to your Mac. No sweeping, cleaning, emptying, optimizing, purging repairing, or tinkering of any kind.

If you have a particular problem, then it might be worth performing some traoubleshooting routine to fix the problem.

If you'r etalking about physically cleaning, then a dry, lint-free cloth is good, or perhaps some of those "wipes" you can get for electrical equipment.

See How to clean Mac products.

If you're asking about "cleaning" in the sense of removing junk software that you do not want or need, more information is required.

Third party "cleaning" apps are themselves junk that you do not want or need.