I delete things in-game, maybe I'm doing it the difficult way but it's the only way I know to see what I'm doing...
You end up with all sorts of random stuff left over if you do it that way. I tend to wander through the catalogues, writing down what I want to delete, then I quit the game and delete everything listed, directly from my downloads folder - which means I can ferret out the recolours as well, which saves time when the game loads as it isn't reading a load of orphaned files.