There are reasons to clear your browser's cookies too, but we're going to focus on the cache here. This is how to do the job no matter what browser you're using.

To clear cache accumulated from applications on Mac, navigate to Finder, hold the Shift, Command and G buttons simultaneously, insert ~/Library/Caches in the tab provided to view your cache files ...

Is your computer running slower than normal? It may be time for you to clear your web browser’s cache to get some of that performance back. Here’s how.

You should clear your Mac computer's cache periodically to help your device's applications run more efficiently. Here's how to do it.