dont sand them, even though it takes off that rubbery surface and makes it strait plastic it kind of ruins the outriggers if you ever wanna sell the goggles or trade the goggles or outriggers. if you dont plan to do any of that though i guess you could sand em if you really wanted to but im sure one of the paints mentioned above would work just fine.
It's only about $1.00 more than the regular krylon. Sanding probably won't help you much, sure it makes the surface grip better, but the real problem here is that you're painting plastic and regular spraypaint has a really hard time sticking to plastic (especially without primer).
The Krylon Fusion really does work well though.