1) Was I on the right track? Is there something here worth saving? Was this a good idea, but it just didn't turn out the way I wanted? If so, I will re-factor within the file.
2) This code is complete garbage. It can't be saved. It's crap and needs to be annihilated. If so, I will start in a new file.
3) There are parts that are exactly as I want them, and others that just need to be thrown in the trash. If so, i may use some copy/paste.
Just my two cents.
Throwing away old code is a double-edged sword.
If you use version control, there is no such thing as throwing away old code =) You can always go back and see if the way you had it before was better, or roll back to another point where things were better before you started messing around.