Originally Posted by schreinertms
Once you get them cleaned, you might want to consider spraying them with a clear lacquer or polyurethane which should project them from future mold growth.
Thanks for the ideas. I will try the black streak remover to see if it cuts thru the ugly to get back to white. It looks pretty bad as-is. I was actually considering painting them with Flex Seal (brush-on) if I can't get them clean.
I'll report back with results once the weekend rolls around...