Hello, Max, I use the Canadian coins as electrodes, too. Instead of reshaping them, I mount them on the lip of the reaction vessel (I use a tall, narrow glass spaghetti jar) using S-shaped silver wire hooks. I drilled two holes through each coin, diametrically opposed and near (about 3 millimeters) to the edge of each coin. Two holes instead of one allows me to flip the coin around occasionally for an even wear. I use a brass-bristled brush to clean and polish the electrodes after each use. ( I use brand-new detailing brushes from an automotive supplies store.) One of the advantages of coins over wire is that the rigid coins hold up better to brushing. There is some loss of silver from the electrodes due the hole-drilling and brass-bristle brushing. But silver is not expensive in comparison to the cost of distilled water. I simply invested ten to eleven dollars in an extra Canadian Maple Leaf. One 30-gram electrode will eventually be dispersed in several thousand kilograms of distilled water, costing hundreds or thousands of dollars depending on the source of the DW.
Best regards, Matthew
