If it’s brown, flush it down — I’d say it’s a useful aphorism in most circumstances. However, when it comes to guacamole, in many cases, the dark hue is really just a discoloration. If you can get over the disturbing visuals, brown guac can be nutritious. In a similar vein, distressed securities may offer tremendous upside, so long as you pick the right ideas. Of course, this raises the obvious question: how the heck do you know which stocks are ripe for big gains and which ones are well past their expira ...