So I've been building up 2 starters from the yeast cake of my last, successful batch. The past week I have had to work, the starters have been in the fridge. I smelled them and they smell like great beer. Nothing looks wrong with them, in the bottom stratified layer there's some green from the hop sediment, but it looks and smells, okay. Do I risk using these in my next batch... That, is the question. Any starter contamination warning signs that I might have missed in my smell/visual test? What would you do?