Rather than deal with the mess of hulls, I went to hulled sunflower chips a few years ago. That has worked pretty well but our winged friends just hoover it up.
Another feeder has safflower...mainly for doves, finches & cardinals so they can eat in peace without having to worry about squirrels --who seem to hate safflower. Then I have three niger (thistle) feeders. I have one fenced-silo type feeder and two tray feeders that have been experimental. I've been trying various finch mixes...especially the ones that tout no waste. So far, that is a pipe-dream. Nothing seems to eat white millet. Not much will eat corn. One mix actually had flax seed. I'm not sure if anything ate it, but with humidity, fog, dew, or rain it makes jello and when it dries there is a crust. I'll never have anything with flax again.
So...has anyone found a decent mix for finches? Points given for a no or little waste solution.