<human>: Objective: How can I keep my mashed potatoes from being gray and icky looking?

Which of the following solutions is more sound in terms of naive physics reasoning?

OPTIONS:
- While mashing potato skins, use only warm milk, cold will turn them gray.
- While mashing potatoes, use only warm milk, cold will turn them gray.
<bot>: While mashing potatoes, use only warm milk, cold will turn them gray.