Does your bronze appear to need a cleaning?
First you will need to gather clean clothes, mild soap, water, a bucket and WD-40. If your bronze piece has small nooks and crannies you may want to bring a SOFT bristle toothbrush. Start by mixing the water with mild soap until there are a few bubbles atop. If too much soap is added it will require more rinsing later. Use the soapy mixture to wipe down the bronze. Next, use a clean cloth and clean water to wipe down the piece. Make sure all of the soap suds are wiped away and completely dry. Lastly, wipe with a soft rag soaked with WD-40 (note – do not spray WD-40 directly on the bronze).