Cat issues

[Moriah Dysteny]

How do I get the cat code to clear on my 2006 GMC Silverado 1500. I have driven it and used cat cleaner I replaced the 2 lower o2 sensors on the bottom. 

[txab]

Have you cleared the code(s) using a scanner capable of doing such? If you did clear them and they returned after doing all you mentioned then it's time for new cats, especially if you live in an area requiring exhaust inspection