Hello, the construction of a thermos we wish to use is such that there is a vacuum seal in between two layers of metal. The outside metal of the thermos is separated from the inside wall, by an inner chamber into which no water can penetrate. This chamber is integral to the function of the thermos because that is what allows it not to allow heat or cold to escape from within. Can we still tovel and use this thermos?
Yes, you can toivel the thermos. A vessel should be toiveled in the same manner that it will be used and it should not be dismantled.
All the best