I usually keep a separate .doc file for whatever story I'm working on called "Notes". I throw every random thought I have while working on the story into this file. Some of the ideas are half formed, some are just observations, but still more are lines I like but don't quite fit. Because I'm an egotistical person, and I know you are too, I thought it'd be a shame for them to go to waste. For those that do something similar I encourage you to post your clever half formed thoughts. I know you have them. We all have clever thoughts. Well... those of us that think do, anyway.
Here's mine: "Richard used to drink something he liked to call his ‘Morning Special’. It was a glass of gin, a spot of ginger ale, and a raw egg cracked in for ‘extra protein’. He'd drink two or three of these every morning on the porch, usually while smoking a cigarette and reading the paper. After the first case of Salmonella Richard took out the ginger ale- he never got sick again."