As to the former question, Macs– keyboard crumbs and dust particles notwithstanding– do not get dirty so much as they collect files that are not needed and should be purged. As to the latter question, either wait awhile for a light cleaning, or find a good app that does a more thorough cleaning.
Macs are designed to keep cache and log files clean automatically, but deeper cleaning involves more– uninstalling apps, finding large and unnecessary files, emptying browser crumb trails, and, optimizing memory and storage.
Enter AweCleaner for the Mac; kind of an all-in-one cleaner utility that gets rid of crumbs, cruft, trails, and unneeded files and apps with a click.
AweCleaner supports three basic cleanup operations.
Cleanup – gets rid of log and cache files, removes unused attachments, empties the Trash can, deletes app support files when you delete an app, deletes duplicate files, and gets rid of large files you don’t need any more.
Optimization – A number of Mac utilities do these, too, but it’s nice to have it all done in a click. AweCleaner optimizes by cleaning memory and storage, and giving you options for startup files that go beyond what you get in System Preferences.
Privacy – Yes, privacy is a big deal these days and AweCleaner’s claim to fame falls into file cleanup– browser cruft, history files, and more, but also includes a file shredder feature which overwrites files to ensure they stay deleted.
AweCleaner is old fashioned. No subscription model. Try-before-you-buy. Buy once, use it until a new version comes along with a different price model to match the improved features. As Mac cleaner utilities go, this one is more expensive than most.
The app isn’t quite a one-click operation, though. Junk files can be found with a click, but you get controls over what gets deleted. Ditto for the uninstaller. It lists all the apps that can be uninstalled, but you click to delete each one. The same holds true for duplicate cleaner– one file at a time, or click to select all files and then delete.
When you get down to it, there is quite a bit of clicking going on for such a hefty price tag, but I don’t know of another Mac app that does this much from one location, so that’s a plus. But be careful and try not to delete too many files too quickly because saying goodbye to a file you need means it may never come back to life.