I have two doubles that were flooded. The metal work is done but the stocks have areas, especially around the lock inlets that
black. Any idea on how to remove those stains?

Hi SWAMPMAN
It sounds like the black stains are the results of rusting Iron/Steel and the tannin from the wood. The usual way of removing such staining is Oxalic Acid applied to the stained area with cotton buds, there is another method if the staining is not to dark fresh Lemon Juice can also work though if it is large very dark patches go to the Oxalic Acid first.

In the states Oxalic Acid is often sold as wood bleach at home centers . I like to rinse with warm water,baking soda and soap. when done.

I restored a Hubalek scheutzen once that had been flooded into a creek for an unknown time. Black stains were in the butt, most likely from water trapped in the lightening hole under the buttplate. Oxalic acid and heat lightened the stains, but some remained. I had to blend the stains into the crotch grain swirls with a q-tip and alcohol stain(Laurel Forge). Owner said I did a too good a job on the refinish with tung oil....lovely rifle. PS: Hubalek was my grandfather's cousin. I was honored to do the work(and nervous as hell!).

I've never tried it, but someone here once used the common rust removing jelly sold at hardware stores. It removed the oxides (stains), but did not harm the wood. Worth a try.