Interesting. Perhaps the alternation of the two is another variable also. Discoloration is after all associated with silver. He had been nebulizing peroxide for like a year before alternating with silver and I did not hear complaints in that time. Perhaps it could have taken this long to develop, and it was just coincidence the silver was started then, and it would be easy to assume it caused it then.
Del, were you using CS around the times you used peroxide also? David