The method of contrast control the Jorge described is also known as latent image bleaching, it bleaches the shadows but not the highlights when the undeveloped print is places in the very dilute bleach solution. I have used this technique many moons ago and I did write an article for the now defunct Darkroom User, I'll look for it in my old files and post it to the articles forum.

Meanwhile you could try my preferred method of dealing with the contrast problems you describe, post flashing where you deliberately give exposure to white light and fog the paper. If you want a copy of ther article I published drop me an email and I'll send it by return. email address is