On more than one occasions i have cleaned wood with TSP.
It will not alter the wood color but it will remove a lot of the grime, grease and oil that has accumulated over the decades in the wood pores, contributing in darkening of a stock.
It will also remove the top layer of a stain that might have been applied at some point.
I do not let it soak in, was and brush the soapy solution and rince right away with hot water, that way there is less chance to affect the wood itself.

I did try bleach on one occasion, but i didn't like the end result. It might have been me and the way i did it but the wood was affected and turned out pretty ugly.
In the end i find that wood is a living medium that does it's own thing... if it has a tendency to go dark it will go dark, anything you will do to it to lighten it will look out of place and not ''real''.
The only real way to get a light colored stock is to find one that is light to begin with.