Although I didn't get any responses, I thought I would report how I made out with my problem. I'd seen a You Tube video of someone saying adding solvent in the gas or soaking in water and laundry detergent would clean the converter.
After considering that the solvent could do more harm than good I opted for the detergent which for the 2000 Altima was relatively easy, remove the O2 sensor in the manifold, disconnect the exhaust and plug the bottom of the CC and pour in the detergent and water through the O2 hole and let it soak.
After draining, rinsing, reconnecting everything and clearing the code, the service engine light never came back on and I was able to pass emissions.
The funniest thing was my local garage told me it wouldn't work and I'd destroy my CC, plus told me I was a moron for even trying (not in so many words). I might stop by there with the passed emissions paperwork and gloat.
Rich