cleaning bronze

Copper and bronze is supposed to tke on a patina that antique collectors love.
If you really want to clean it though..A caustic product like CLR Clear would work.
Here's what I would do... From Hobby Lobby, get a bottle of safety flux. It is especially designed for copper and brass, thinner than water, labor free, will not harm surrounding materials any more than Windex would. After than gets the tarnish and green patina off, wash with Windex, water rinse, dry. Now the labor... Maguire's All Metals polish will leave a protective film but it aint much or very long lasting. Better than nothing though. Cleaning its white residue from small details is the only labor.