[Q] What do you use to clean the back of the white Nexus 9 topic

I haven't get the magic cover for my white Nexus 9 yet and there are quite a bit of stain on it already (oil stain from my hands), and with the material that Nexus 9 has, it's pretty hard to get it off with just my breath and soft cloths..

Any suggestions? What do you use to clean the back cover?

Thanks in advance.