What we use on our Herefords faces & legs is a purple looking soap at TSC. I think it's called bright white or something like that. It's not expensive & it does a good job. Don't get fooled by it's purple looking color just put it on & let soak but not too long or the calf will turn a reddish pink. Works for us.
Thanks everyone. We also use Bright White on our white pigs. Most are York crosses, and can get pretty dingy by show time. We will also try the bluing. Sometimes the most effective products are the old standards!