Hi Terry - I cannot believe you can't obtain washing soda in Canada. It is the stuff grandmas used before detergent and they used to boil their clothes in a copper. If you can obtain some scrap stainless steel, that is the best anode (+) and use stainless wire to hang everything. Stainless is the best conductor. I don't know how powerful converted baking soda is but with washing soda the ratio is one pound to a gallon.
Re. screws, I have not tried it myself, but maybe if you put them into a stainless sift and connect that to the diode, that may work. If you try that and it works, let us know please.
Bob