Hi Sherry, unfortunately you don’t. Resins don’t like moisture. You won’t be able to use milk in its liquid form and have it cure in resin.
As for yellowing, unfortunately, all resins are going to yellow over time. Resins with UV inhibitors and stabilizers help extend the time before yellowing occurs. However, things such as mixing off ratio (even though it still can cure without tackiness), putting over an improperly cured lacquer, excessive heat, and or constant exposure to sunlight can speed up the yellowing process. How long the epoxy will last in its clear state is very difficult to predict.