I bought some of that Lyman walnut with the red rouge once. It left a mess of rouge residue all over the brass inside and out. So like you, I had to tumble again in clean media to remove the rouge. Why do twice what should take once? I washed all the rouge off the walnut so I could use it up.
Are you cleaning brass or making jewelry? I want the dirt and loose carbon removed and an hour in walnut will do that and polish some. I haven't found the walnut any more dusty than corn cob and it holds up better.
The trick with that stuff is to mix it with walnut media. Go 30-40% Lyman tuff nut next time. You won't get that red dust on the cases anymore and your brass turns out very clean and polished..