Yup. Even disregarding the problems mentioned in the linked post, it isn't going to work well for real-world applications. Fresh or saltwater, any vessel is s

Yup. Even disregarding the problems mentioned in the linked post, it isn't going to work well for real-world applications. Fresh or saltwater, any vessel is subject to corrosion and the accumulation of grime (or worse, like barnacles). In the demo video, note that the demonstrator is using gloves and isn't even touching the "coin" directly, but using tweezers.