STEP 1. First you have to click on “Preferences”. Now you will be able to see a dialog box, then you have to click on “Security”.
STEP 2. Now you have to click on “Show Cookies” button under the “Accept Cookies” preferences. Now you will be able to see the list of cookies stored in Safari.
STEP 3. In order to delete all the cookies, simply click on “Remove All” button or you can select the cookies you want to delete and then click on “Remove” button.
STEP 4. After that you have to click on “Done” button.
In order to close the Preferences box simply click on the red circle in the upper left corner and then you can browse. In this way you can delete cookies on Mac OS X using safari browser.