For some reason which I haven't yet figured out, I've been saving older style large size magnesium filled flashbulbs.
Would drilling a tiny hole and filling the bulb with saltwater work or does the magnesium need to be in a central core?
The casings are not glass, but some kind of plastic on some, so alternately a number of holes could be drilled in the casing and it can be immersed in a larger vessel with the saltwater.
A while back while doodling, I came up with a spark gap circuit that neatly gives plus or minus pulses from a single polarity supply. I'll see if I can locate it.
Just because it has a patent application or is patented does not always mean it really works.