Here’s a basic cleaning solution, plus steps on how to clean your bird feeders:

1. Fill a plastic tub or your sink with 10:1 bleach solution (10 parts water, 1 part bleach)
2. Put on rubber gloves
3. If the bird feeder comes apart easily, break it down to its parts, and place each into the bleach solution
4. Using a stiff scrubbing brush, remove the debris, paying careful attention to the platform and perches.  If the bird feeder or certain parts are very soiled or molded, let them sit in the bleach solution for 10 minutes.
5. If you’re cleaning a tube bird feeder, you will need a long cleaning brush.
6. Rinse the feeder very thoroughly.  Use hot water; some birders prefer boiling water.  This is important!
7. Dry the feeder with a towel.
8. If the bird feeder is made of wood or is a tube feeder, let it air-dry overnight before refilling with bird seed or suet.