It's really simple. Getting silver isnt much of a problem, you can get a Quarter older than 1963, and cut it in two, this will give you silver. Or, you can get one of those commemorative ounce things, mine was of the pope. I got it for a 20.
As far as the machine goes, it's very straightforward. Get a power supply from a printer or similar. You want between 24 and 30 volts. If you have a speaker around, you can find the polarity (the + and the - ) easily. Strip the two wire ends from the power supply, don't cross them, and plug the supply into the wall outlet. Touch the wire leads to the speaker terminals. If the speaker jumps out, you have the positive wire connected to the positive speaker terminal. You can do the same thing with a household battery. Works great when dealing with a radio. Get an LED of the same voltage, and wire it in on the positive line. There is a scientific reason for the LED, it's way over my head for explaining, but it works. Anyways. Connect the positive line with the LED to an alligator clip. Clip one piece of the silver to the clip. Take the negative wire from the power supply, and run it to the other alligator clip, and clip it to the other piece of silver.
You will need a glass basin, fill with distilled water. It has to be distilled, again, go ask a scientist why, I dont know. My nanners work so whatever. "N-Y how... Attach one clip with silver to opposite sides of the basin so that the silver pieces are under the water and NO PART of the alligator clips or wires, or any other thing comes into contact with the water, or your silver.
Plug it in, and you should have something strong enough to spray in a week or so.
Use a couple coffee filters to filter out the crud that will be created as a byproduct of this very simple operation.