A Circular Polarizer Filter (CPL) is used on a camera lens to lower or adjust the amount of light rays which enter the camera lens. The reflections are usually seen on the surface of water. The filter is also used to help create a greater contrast between white clouds and a blue sky. The filter is manually adjustable once on your lens – the photos below show the filter adjusted to allow reflection and then adjusted to filter out the reflections. Adjust the filter once it is attached to your lens.
Increased Contrast from the CPL:
The Circular Polarizing Filter on Water
The filter will not always remove ALL of the reflections, but will reduce the reflections.