I've done a little. The best articles I've read on it are Bruce Barnbaum's piece in _Mastering the Black and White Fine Print_ (_Photo Techniques_ special issue no. 11) on local bleaching, and Les McLean's description of general bleaching in his book.

I occasionally use local bleaching. If I want to get a little more luminosity in a highlight, I pull the print from the fixer, apply a potassium ferricyanide solution with a brush, applying and rinsing as Barnbaum describes, and when it's about right, put it back in the fixer to clear the bleach and bleached silver (it continues to bleach somewhat in the fixer), then wash and tone as usual.

It's not that mysterious once you've tried it. It helps to have an area that is well defined, because the bleach will work faster on light areas than dark areas, so orient the print so that you have a dark area below the area to be bleached to minimize drip marks. This fact also means that contrast will increase in the bleached area.

Ilford Galerie and MG (RC or FB) seem not to bleach well in my experience. Oriental Seagull, Cachet Expo, and other papers take to it more readily.

Les's process involves bleaching the whole print, which will increase overall contrast and push up all the highlights in general.

Also, potassium ferricyanide is probably the most poisonous thing we use in the darkroom, so be careful, don't point brushes on your tongue (one of those things painters do that never really made sense to me), keep out of reach of children, label bottles clearly, etc.