Claus Schlund wrote:
"To which I say – thank goodness this is no longer possible! I often use isopropyl alcohol when applying weathering watercolor paints, and the isopropyl alcohol used to react with Dullcote and yield a chalky colored finish, even when I allowed time for a long-term curing of the Dullcote for weeks. This is typically what I did NOT want for most freight cars. While I agree it can be an asset in some specialized cases, it was typically a problem for me."

You do realize this process is controllable, right?  Mike Rose wrote several articles and filmed how-to videos on how to use this effect on more recent rolling stock, showing how to both apply and reverse the effect.

 

Ben Hom