I would not substitute the raw egg yolks for anything else, because only those precious, whole, raw, organic eggs will stimulate your liver like nothing else can! i called myself a raw vegan for close to a decade and i was adomant about not touching eggs, until I realized that you get so hung up on the term "vegan", and forget the real goal of your journey: HEALTH and of course, you don't want to cause harm to any living being.
When I practiced veganism for years and my vitality fluctuated up and down I got determined to detox completely and tried just one of those egg-yolk drinks. Believe it or not, i got drastic results literally overnight and now, i am convised that in nature, people were meant to eat eggs from time to time. They are also tasty and they look darn good too... in those oval shapes of theirs and that delicate shell color! Not to mention how gorgeious the yolk is to look at.
Yes, on the subject of metal... metals are very reactive elements. Metal reacts fast with everythng that it comes in contact with. So it is best avoided, otherwise it will modify the chemical formula of your food. It is not for no reason that asian nations use wooden chopsticks and old european cultures use wooded utencils to cook and eat with. Aluminum is amont the most toxic metals, so NEVER cook in aluminum pots. Next is copper. I recommend using #1 unglazed,pure clay, #2, porcelain and #3 glass. so whatever you do, do not use metal.
Try the drink and watch your hair in the morning! it will be shiny and bouncy. try it the next day and the next and watch your hair become like the models from the TV comercials. no joke!