I'm not certain I would try collidal Silver after reading this. Apparently it can turn your skin blue, and can possibly build up in the body over time, seems it doesn't readily exit the body.
I saw a post on another forum regarding using Oregano Juice, and distilled water put into a nose spray bottle, as well as you could try Xclear which is a grapefruit seed extract nose spray which I just started a few days ago and will see how it goes. Also the netti pot saline rinse is a good idea.