Though most cookies are useful for website to identify users’ informance, accumulating cookies saved and stored on hard drive may slow down the PC and even far worse to possibley enable hackers access to your privacy, learn more here on how to delete cookies in Safari.
Well, you may simply use a PC clean up software to clean cookies efficiently for you, For this, try Cloud System Booster. Or else you can choose to delete cookies by yourself. Here comes a manual guide on deleting cookies in Safari for your reference. You can also click here to know more on how to permanently delete cookies.