Black fuzzy stuff on wall of sourdough starter jar

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Today is day 6 of my rye/all purpose sourdough starter. Ive noticed some black fuzzy stuff on the wall of my jar- not on top of the starter however. Is this mold? Should I chuck my starter? Thanks!! 

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That looks like mold. And if it isn't, better be safe than sorry.

Carefully try to get a bit of starter that hasn't been affected yet and continue, that should solve it.