Why do some colors of glass seem to 'stick' more than others

[Jenna]

In my experience, it seems certain colors of glass pick up kiln wash or stick to molds more than others. Can somebody please explain why that might be? I use mostly transparent glass, both BE and Sys96.
I realize opal glasses stick more than transparent, which is another interesting question, but I am asking specifically about the differences between transparent colors. For example, One of my favorites, deep Aqua (5333-96) seems to stick every time.

[Jordan Kube]

Certain colors are more chemically active than others.