I have been using the vials (glass and plastic) with great succes with just about everything under the sun except iodine. Iodine is nasty stuff. It's a very outdated method of water purification that was designed at a time when medical/chemical science was nowhere near where it is today. We know a lot now about the negative long term effects of iodine on the thyroid gland as well as other things these days. If you read Doug's write-up you'll find that he does not even recommend it anymore. My doctor tells me to stay clear of ingesting anything with iodine in it and he gave me a whole list of reasons why. It's really nothing short of a slow poison. Just a little FYI to try to keep you safe and healthy. The MP1 tabs are not much different than the way urban treatment facilities treat water (if I am remembering correctly). Please also be aware that anyone (such as a wife or daughter since its more common in women) with any type of thyroid problems should absolutely stay away from iodine tabs without actually showing them to their doctor! They could very well kill them and I don't mean the slow way either! I'm not saying that MP1 tabs are great for you but they are far better than Iodine. And of course there is always the oldest method..... boiling.