I have not done this before. Will try right now. We have six 4x6x1 *powerful*, and mean the slam together blister causing kinds of magnets that you talk about. I've done that a couple of times.
We use these for you name it. Have one in kitchen were SSKI and Lugols 1oz bottles reside.
But always more to learn. One of the worst experiments was placing one with the 'wrong' pole facing the back of my neck. This was when I first received them. The impact on the thyroid was awful. I was looking to relax tensed up muscles in my neck, but had the unintended but now too obvious influence on the thyroid. Won't do that again. They are amazing tho how fast they will dispatch even a simple leg cramp for instance.
Magnets are very cool.
I will be asking more about them. Off to slurp some dual tap water experiments....