Introducing "Dirty, Nasty, Filthy"

I've been considering a numerical ranking system for pitchers on a 100 point scale, but I get really bored with numbers some times, and would rather have a more entertaining ranking system. So, for now on, when I write about a pitcher, I will rank him as either Dirt, Nasty, or Filthy depending on how good he is. Each ranking will be used in place of a number grade and the following chart explains what each term means numerically:

Term -- Score

Filthy -- 90-100
Nasty -- 80-89
Dirty -- 70-79

I'm still considering which terms to use for pitchers that score a 69 or below, so if you have any suggestions, feel free to let me know.