Dennis,

Yes the oil will collect a bit of dust but I don't worry about that.  Just rub them down if you want to take them out to a show otherwise the great benefit of the dust and oil mix is that you have a wonderful harmless preservative that slowly builds up.  If I take one out to a show I simply clean off the tinwork and leave the rest dirty and preserved, then respray the tinwork when I get back home.  As you will know when you have a lot of tracors and implements its a hell of amjob keeping up with them and this simple procedure takes all the work out of the job.  Marvellous for old timers.

As I said, I spray them twice a year - generally autumn and spring.  If I have visitors then if I have time I will just rub the tinwork down and you have a nice fresh looking tractor to show.

Never seen 32 in wheels on a Challenger

John