I know not to expose a fermenting carboy to sunlight, but is it OK to expose a yeast starter? I have two of them next to a window with blinds that are ineffective at blocking sunlight. I didn't think about it until now. May I proceed with brewing or should I throw these yeast starters down the drain?
If the starter was not hopped, you should be ok since the hops are needed to produce the skunky flavors.
The UV radiation in sunlight can damage yeast cells, but they are capable of self-repair to a degree, so there should still be plenty of viable cells to continue fermentation.
It's a good idea to not pitch the spent starter wort in general, here, I would definitely decant most of the liquid and pitch just the yeast to be on the safe side.