But how do you actually verify the source? Let’s assume that some amount of conflict metals are laundered through other countries, and commingled with ‘clean’ m

But how do you actually verify the source? Let’s assume that some amount of conflict metals are laundered through other countries, and commingled with ‘clean’ material (which is usually how it happens); how do you figure out whether your supplier is using this material? Do you just trust any documentation they provide? If not, what is it that you’d do?