Green brass.

If you want to clean it, you used to be able to find Poco (a mild acid) and it would clean it all off. You could also get a brass wire wheel on a drill and it takes it right off, so does spraying it with corrossion block over time. I would wash your bilge really well with boat soap and freshwater and definately at least spray them with corrossion block, and all of those parts are indeed brass.

Woops, meant Bronze fittings......the brass wire wheel made me repeat brass instead of Bronze. Left Baltimore, M.D. Sunday in a 50' boat that cruises at 21 knots and am in Jekyll Island, so it's been a lot of hours the last 5 days, cold out, and still have to get to Key West but I do have DPS.....LOL.

Only if the the bilge pump is connected with wire nuts.

The Rule 3700 GPH bait pump does have some sketchy electrical connection that is covered with electrical tape and looks like the wires might be just twisted together underneath the electrical tape.

I owned a pilothouse trawler years ago and all the portholes were green verdigris.
One weekend I decided on a major clean up. Using a Dremel and rough sand fittings, I cleaned each fitting, then again with a milder sanding.
Within a few hours the hull and my entire body was as green as the Hulk!
Portholes looked great...for a few months, then back to green.
Moral: forget it. If it does the job, leave it and save the energy for items that need constant work, like varnish!

Kafue, responding to you not Joe. I always heard that the red burnish is the thing to watch for in a bronze fitting, no? Green doesn't mean a thing in terms of deterioration? In fact, you can remove it, but it will return.

Never seen the red. Just the green.
I came to view it the same as old leather in a classic English sports car, or the cracking of an old oil panting: Patina.
Adds character.
Cheers.

Green is ok, although I prefer to spray the ones on boats I manage with corrossion block and they then aren't so green. Red is definately bad because that is generally electrolysis eating the metal.

We are talking about Electrolysis here, you have a bronze seacock, attached to a bronze thru hull, attached to plastic. Galvanic corrosion is generally when you have say a stainless seacock attached to a bronze thru hull, or 2 dissimilar metals touching each other, stainless screws into Aluminum, etc. etc.. Any thru hull or metal part with sea water in it or passing through it, needs to be bonded to keep electrolysis down to a minimum or can and will turn bronze red as it attacks it. But you don't get galvanic corrosion from Bronze attached to Bronze which has seawater in it.

• Electrochemical corrosion or wet corrosion. This type of corrosion arises from the creation of an electrical element in a watery environment. This electrical element is build by two different metals with an electrolyte in between. The best example for such an element is a battery as used in every yacht or car. This electrochemical corrosion is also known as electrolysis or galvanic corrosion. As this corrosion is the biggest danger for all underwater metals we will go into depth how avoid this.
  
  
• http://www.yachting-life.net/new index/frames3/electrol_frame.htm

Galvanic corrosion (sometimes erroneously called electrolysis) can damage or destroy underwater metal parts of boats, dock hardware and other equipment. When two different metals are touching each other or are electrically connected by a conductor, and are immersed in an electrolyte (an electrically conductive fluid, like salt water) an electro-chemical reaction can occur. One of the metals (the “least noble” metal, called the anode) will corrode faster than it normally would, and the other (the “most noble” metal, or the cathode) will dissolve more slowly.

http://www.westmarine.com/WestAdvisor/Preventing-Galvanic-Corrosion

"Electrolytic corrosion results from the action of an imposed direct current. Galvanic corrosion results from self induced currents which in turn have resulted from the electrical potential between two dissimilar metals in contact."

http://www.copper.org/applications/plumbing/techcorner/pdf/galvanic_corrosion.pdf

The bronze valve that turned green did so because that is what bronze does when exposed to the a damp atmosphere, not because of electrolytic or galvanic corrosion - speaking of which I see the claim that both are the same thing seems to have vanished from post #17.

Yes, Green is normal for bronze when exposed to salt air/water. A reddish color is electrolysis, which is what Captholli was speaking about, Bronze turning a reddish color. I've seen Bronze exposed to galvanic corrossion with sea water in it (a s/s thru hull someone put a Bronze seacock on, the bronze turned dark green/black in color, but anytime I've seen it a reddish color it's been electrolysis.