Bonny unless you are reasonably experienced in wood finishing making a wood lighter by bleaching is possibly one of the hardest things to get right enough for good end results, so best left to an experienced person.
That said I have used two methods the first is the application of strong household bleach. This is good for removing many types of applied wood stains but not that effective at removing the original colour of the wood, you leave on the wood for about fifteen minutes wash off with clean water allow to dry and then check the colour.
The other method is to use two chemicals that are on the not so good for the human body, though this method does remove the timbers basic colour and is the best I have found for lightening timber.
First you apply a lye mixture as you are close to the UK this is made from Sodium Hydroxide also known as caustic soda, this makes the wood look dark.
While the wood is still wet with the caustic solution you brush on a 30% solution of Hydrogen Peroxide and this takes the colour out of the wood.
Start by leaving the mixture on the wood for five to fifteen minutes then wash the mixture off with a good helping of clean water and allow to dry. Just repeat the process until you reach the desired colour you require, though I do normally go a couple of shades lighter then apply a wood stain to even out the whole effect.
Wood bleaches can be obtained this side of the pond from a company that goes by the name of “Liberon” who are one of the largest suppliers of wood finishing products, you can order via the net also their web pages are extremely helpful.
I have found that both methods do not cause any finishing problems if they are initially removed from the wood with a good amount of clean water.
Bleaching wood is not for the feint hearted and there is a lot that can go wrong and put you in a worse position than when you first started.
You know there is nothing intrinsically wrong with a rich dark and beautiful Walnut gun stock.
