Weathering gondola interiors

[Angus Shops]

I have a brace of gondolas that require weathering. What sort of crud would you expect to see in the bottom of a car in typical service? I know railways have requirements about the cleanliness of cars being returned empty from a consignee, but I’m certain most gondolas would accumulate a fair amount of debris.
Thanks in advance.
Geoff

[CNR5529]

The short answer is it really depends on what service the cars are in. You could find generic dust and crud, wood cribbing bits, steel banding, build up of whatever bulk material the car was hauling, a thick coating of creosote if in tie service... some of my gons just get multiple generic washes of dirt, soot, grime, rust and mud tones, until it looks convincing enough.

Here is an interesting post about the subject, with some photos that should provide inspiration:
https://www.google.com/amp/s/lionelllc.wordpress.com/2012/11/16/freight-car-friday-empty-gondolas/amp/