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To thoroughly clean a birdhouse…
1. Open the bird house or partially disassemble it for proper cleaning. Bird houses with swinging sides, hinged roofs or removable fronts are the easiest to clean.
2. Remove all old nesting material and scrape out any feces or clumped matter. This material should be disposed of in a plastic bag to prevent spreading any parasites it might harbor.
3. Scrub the house thoroughly with a weak bleach solution (one part chlorine bleach to nine parts warm water). Be sure to scrub all corners, the entrance hole and drainage and ventilation holes.
4. Rinse the house well in clean water for several minutes to remove all traces of bleach.
5. Dry the house thoroughly in full sun for at least several hours. This will break down any remaining chlorine and ensure there are no moist crevices for mold or mildew to grow.
6. Inspect the house for loose hinges, protruding nails or screws, prominent splinters and other hazards that can injure adult or hatchling birds.
7. Check that all ventilation and drainage holes are unobstructed.
8. Reassemble the house securely and check that all screws and joins are tight. If the house converts to a winter bird roost box, assemble it in that configuration after the breeding season ends.
9. Store delicate gourds or clay bird houses for winter so they will last longer, or return wooden bird houses to their hooks or posts so they can be used as roost boxes for cold winter nights.