How do you change skin or hair color on Poptropica?

The easiest way is on 24 Carrot Island : Inside the diner is a drink fountain that dispenses many colors and combinations of colors. If you drink from the fountain, your hair color will change.

Also, you can buy the Colorizer at the Poptropica store, and then you can change your hair and skin anytime you like.

If your computer does not use the keyboard combination CTRL+SHIFT+H to open the browser history, pushing these three keys simultaneously will toggle thru every available hair color. (CTRL+SHIFT+S will change your skin color. Note that you cannot just change back to the color you had, but rather keep going until it comes back up again.)