Hmmmm. None of my ferrules get dirty. Nor any of my shafts either.
But then, I like to think that I chalk properly and wipe any excess off with my hand after.
When you are in the habit of deep drilling a piece of chalk with your shaft standing completely erect, yes, the chalk will get all over a ferrule, and your shaft.
If it is happening to more than one or 2 different ferrule materials, I doubt that it is the material that is causing the problem.
I have 2 retips to do this aft. Both ferrules look like someone painted them blue on purpose, yet none of mine get that way.
Here is a small vid.
https://www.youtube.com/watch?v=DE1KNOp0g5M
Don't want to be bent over on the price. Don't blame ya one bit. Think of how we feel when we purchase the material in 3 to 6 foot lengths.
It is what it is. It would seem, the better the material, the more expensive it is.