To clean your pool rails or ladders you must first remove them from the swim pool. They are normally wedged in sockets called deck anchors. By lifting up the escutcheon plates-the decorative circles around the rail/ladder where it goes into the swimming pool deck, you will see the bolt that raises the anchoring wedge. Using a wrench, you can unscrew this bolt about a half an inch. You may then need to knock down the bolt to drive the anchoring wedge down, freeing the rail/ladder. You now should be able to lift the rail or ladder up and out of its sockets. If the rail/ladder is stuck, you can use a rubber mallet or similar tool to bang the rail just above the deck to break it free.
If the handrail/ladder still will not come out and you are sure the wedge is knocked down, you can try using a car jack to get the rail out. By putting the jack under the hooked part of the rail (you may need to use a short piece of 2 x 4 to reach), you can apply force upward. Be careful not to jack it too hard as you can deform the rail or bend it. Try lifting the jack just enough to apply pressure and hitting on the rail just above the anchor with your rubber mallet. In most cases this will free the rail.
Occasionally, you may come across a rail that will not come out, even with light pressure from a jack. The rail has probably corroded to the anchor, and you may have to distort or destroy the rail to get it out. You will have to determine if replacing the rail and/or the deck anchor is worth it at this point.
Now that you have removed the handrail/ladder you can clean it. The best cleaner for this is one like Naval Jelly. Use a plastic scouring pad (not steel because it scratches the rail) to scrub with. You may want to disassemble a ladder to make cleaning easier. Be sure to rinse thoroughly after cleaning to remove all residual chemical from the rails. Note: If you can't find Naval Jelly at your local hardware store, try using Coca Cola.
Now that you have cleaned them well, you can apply some car wax to them if you like. This will help protect them from the elements longer. If you close up your pool for the winter, this is an ideal time to remove and clean your handrails and ladders. By cleaning them, you will maintain that new look much longer.