Disassemble the fixtures so each brass piece is separate from the others. For example, remove door knobs from spindles and wall plates from lighting assemblies. Place the brass pieces into an old slow cooker.
Fill the slow cooker with enough water to cover the brass fixtures by 1 inch. Add 1 tablespoon of liquid dish detergent or 1/4-cup of household cleaner per half gallon of water. Cover.
Turn the cooker to low and let it "cook" 6 to 10 hours, or overnight. The soapy, warm water softens the paint and caulk. Much of the material may fall off the brass during the soak.
Remove each piece with tongs when you are ready to work with it. Let the brass pieces cool enough to handle.
Rub loose, wrinkled paint and caulk from the fixture with your fingers.
Scrape the remaining bits away with a plastic putty knife or a wooden Popsicle stick. Don't use a metal scraper, or you may scratch the brass finish.
Dig out remnants of paint and caulk from textured details with a fingernail brush, the corner of the plastic putty knife or wooden toothpicks.
Replace the brass pieces in the slow cooker to soften stubborn materials. After a few hours or overnight, repeat the removal techniques until the piece is clean.