cookies and how to stop them

running OS X Mountain Lion on MackBook Air (mid 2011) and MacBook Pro (early 2012), I want to stay cookies free (only turn them on when mecessary), so I surf the net with this set up:

1. Safari 6.0

• Private Browsing ON
• Block Cookies always ON
• Do Not Track Me ON

2. Exstesion installed:

• Do Not Track Plus (NO sites allowed)
• Adblock
• Click to flash

3. App from Apple Store

Cookie

I regularly reset Safari, remove All Website Data in safari Preference, Remove All Data in Cookies, check that no sites are allowed in Do Not Track Plus, and yet every time I find loads of cookies and data stored in my computer. It's seems like a pernicious disease one can't get rid of.

What do you do to stay cookies free online? Is it an attainable goal?

Thanks,