This script allows you to extract and apply saturation to a layer. When you extract, it adds a new layer with the saturation values (in gray colors). You can then use curves, brightness/contrast or the dodge tool to correct saturation. When you are okay with the adjustements you can put back the saturation by applying it.
This script adds every single layer to the background.
Every layer matched with the background is saved by the name of the layer in a directory called with the name of the image.