When I was in the Troopers we wanted yellow tape it matched our uniforms and we put blue stripes around the front for visual effects. So it is obvious that the tape you are using is fading and you really want the white. Like what has be mentioned I would invest into a better quality tape.
I had a little laugh when I read this. I don't know exactly what you meant, but how it took it was that you guys just got white tape and just never replaced it, planning on it turning yellow on its own. Although, if I were to use common sense, I'd assume you guys actually bought yellow tape. But it was quite comical to think the other way. Thanks for the laugh either way you meant it! Haha.

Oh, by the way, along with this post: unfortunately, I've not run into that problem. I have run into dead skin cell build-up in between the layers of tape. And in that case I just retape them. But I do naturally have sweaty hands when I play and I've never run into a yellowing problem.