great brushes for the ports of hummingbird feeders. All other uses suggested are dubious at best. these brushes are soft and therefore the bristles bend, then wear out rather easily (with weekly use, about 6 mos at best). Not a big deal but I wish they were stiffer--being soft they require a lot more brushing than a stiff bristle would to do the same job.
I love these brushes. It makes cleaning our humming bird feeders a lot easier. Thank you for these.