he uses gold leaf on pots after fire, you can also get silver leaf. I think that is the best use for them as you actually get the properties that make them so unique. You could also metal turn them, etc... for cool effects. I've also heard about using some gold in the kiln but am not sure what the process is called, it's also used for gold designs like gold leaf, but is suppose to be very tricky to get right, though it might be more permanent for dinner ware.
But like John said, why use gold for reds if you can use copper? I haven't mixed up a