1. Colloidal silver is its own preservative cool dark place don’t refrigerate.
2. For colloidal silver, shelf life of about a year or more. Glass, preferably dark container.
3. Technically, vodka is mostly distilled water so that shouldn't harm the product much, just make it weaker. I'm not sure if the alcohol itself would interact with the silver though. It would probably be wiser to mix the silver product with the alcohol immediately before using rather than mixing them before long-term storage.
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