Sour flour you can smell. If the infestation isn't real bad, it's still ok. Of course, I'm the "waste not" mindset due to growing up so very poor. Waste was anathema to us.

Though if you freeze flour, it kills the weevil eggs so they won't hatch. The eggs are SO tiny that it's impossible to be rid all of them when the flour is processed even in the factories. That is why, if flour sits for too long, it ends up with weevils. I learned about freezing it from a couple of individuals who live off-grid.