volcano webcams
They've been running for days... granted they're stationary, but whatever lens (or window the lens is behind) isn't pitted, or even dusted up..... You'd think at that proximity, even if all were upwind (and the two I'm watching are in opposition to each other, it would appear), you'd think there'd be SOME residue. No big conclusion being drawn (or jumped to) here, just a simple observation.