Slugs and snails

I have heard that thin strips of copper give of a small electrical charge when they are earthed into the soil. This "electric fence" keeps the critters out.
My question is will thin strips of allumimiun do the same thing :?:

It wont work the charge is made by the copper reacting with the slugs slime. Hence to keep the copper working you need to rub it a couple of times a year with sandpaper, to rub the oxide off.