Construction Equipment weathering

Due to the Barrie train show I now have three Norscot made Catapillar models, though they say they are n scale I would put them more at 1/144 with the excavator being the closest to scale. When I got them they had that diecast toy car look all shiny and clean, needing serious weathering.  Sadly they are missing the glass to the windows which if you look at the 906 below makes the cab look incomplete. Another issue is all the filled in sections around the armatures and implements that needed drilling out and some cylinders that aren't attached to the arms they are controlling like on the 315 excavator. For the weathering I used washes of black and brown craft paints, after saturating the model I would let it sit till almost dry then wipe off the most of the paint, this would allow for it to get into the tight comfined spaces to help bring out the depth. After that I would dry brush in light rusty and dusty colors to really make the model stand out.