If you cant find the washing soda, you can use the arm&Hammer baking soda. The washing soap contains sodium carbonate and the baking soda is bicarbonate. The difference in one water molecule, baking soda works just fine. If you feel you really need the sodium carbonate instead of bicarbonate, just put the baking soda in a pan in the oven on high for a little while and it will convert to sodium carbonate. I have also read where 20 mule team borax will work. I think basicly you just need some sort of electrolytes to make the electrical exchanges more efficient. I remember in science class we would put pennies in a solution to copper plate stuff. Cant remember much about it, its been a while, but plating those traps once clean would be a good way to preserve them for future generations.