1-Buy clothing dye.
2-Boil a lot of water (because it has to cover the whole goggles.) and mix with the dye.
3-Make sure you disassemble them.
4-make sure the water is simmering the whole time.
5-check on your goggles to get the right color.
6-Wash the foam thoroughly with cold water.
For the color, the one you can do are basicly everything darker than red, so, no yellow, orange, pink, any of those kind of shades!