The results of a simple surface cleaning with mineral spirits may amaze you. Polish buildup and the dirt embedded in it can muddy the finish, but will wipe away. Don't use stronger solvents; they might dissolve the finish.
Soak a coarse, absorbent, clean cloth with mineral spirits and wipe the finish. Keep applying and wiping until the cloth no longer picks up dirt. Then do a final wipe with a fresh, clean rag.
Don't throw away the cardboard tube from wrapping paper! Tape the tube to the end of a vacuum cleaner wand to reach cobwebs in ceiling corners or dust on fans. Reach all the way under beds and furniture, or flatten the roll to vacuum narrow crevices. Make it a permanent dusting wand by wrapping it with duct tape, and it'll stand up to years of use.
To clean your birdbath, put two cups of vinegar in the bath and fill it to the brim with water. Cover with a trash-can lid, and let the bath soak overnight. Scrub and rinse well.
To attract butterflies to your birdbath and avoid algae, put a layer of builder's sand in the bottom of the birdbath.
Add a pantyhose leg stuffed with oat straw (available at amazon.com starting at $10) inside to your water for an algae-free birdbath.