unusual question on dust

[olsbooks]

Now working on a diorama with a car that has been sitting in a barn for years.  The car is "Perfect" other than  heavy dust buildup on top surfaces.  Working with 1/16 scale and the car is bright red and already completed.  Testing a dusting/misting a thin coat of paint i find it tends to grab the sides. It looks forced...which it is.  Masking is impractical but need it to stick like paint. Chalk looks best but unable to seal it without some "blow" or sticking to sides.   Suggestions?

[stitchdup]

I've recently purchased some ak enamel dust coat stuff for aircraft. I haven't had the chance to try it yet but from some builds i've seen it looks like it works well. Its in the aircraft landing gear packs. You might also find something in the warhammer/citadel type paints or model railway detailing washes

[dustym]

I know this wont help, but I had a couple of models that are rusty and dirty, but whenever i dusted the other models, i left these alone. Now after 20 years, they look about right.