Jim Betz wrote:
"I do not know why this is true ... but I've found that if you use a wire wheel in a dremel and clean the Kadee wheelsets by running them in an old plastic truck and getting them to be bright shiny - that they
do not pick up dirt as fast as they do with the blackening on them. We can speculate on the reason - I prefer to just know that it works and use them with very few problems with dirt build up. As in - I have used them for 2 or 3 years without any build up ... recleaning them, when necessary, is as easy as removing them and running them thru the make shift 'dirt lathe'."
I used to to do this, but I've found the opposite - the wheel treads oxidize again fairly quickly, and there's no getting around the porous sintered iron picking up more crap. Plus I've had a few fly apart when sent through the "dirt lathe". No, I just replace them when I see them, bag them up, and sell them off to less discerning modelers.