Absolutely! We love seeing what mixing our shades will do and we love seeing multi- colored strands too! (Tag us on social media so we can see your fabulous results!)
There are lots of people who use multiple oVertone coloring conditioners at once -- including our own staff!
If you have multi-colored hair, all you need to do is section! When trying out multiple colors, we recommend staying within similar color families that are next to each other on the color wheel. For instance, pink goes well with red or purple - but mixing pink with green or teal may end up with some funky brown or grey results, since they cancel each other out as opposites on the color wheel.
If you have multi-colored hair, all you need to do is section! Do the best you can to section out parts of your hair that are the same color, clip each section separately, and then apply color to each section individually. The conditioner is thick enough that if your hair is dry, it should stay put wherever you apply it!