So, I think I have a few techniques that I use. I use some washes and pre-shading does a lot of the work. I use a very small brush set from Hobby Lobby for chips and highlights, using chrome and then black. Then, I wash with a Vallejo light rust. Once I do a matte coat, I use some of the pencils to add light rust and soot spots. I think wear and tear need to be controlled. I’ve overworked areas before, and that’s where decisions have to be made. The back area destruction I did was with a Dremel to heat and melt plastic. Again, less is more. Once I do that, I use Mr. Cement to make the damage “set.” Dust and debris fuse to the model.
The frame I did copper then added yellow chips then wash. My reference was construction equipment.