Weathering and Washes

I am in need of help. I am currently deployed overseas. I was able to get some kits sent to me and a limited number of paints. Black, Green, Brown, Gunmetal, and Steel. Is there any suggestions on using these colors to weather modern armored vehicles. Any help would be greatly appreciated.
Thanks everybody for your help.

Steel is my choice for drybrushing on any AFV.

Depending on the shade of brown, you could also use it to drybrush a soiled effect.

Black will work very well for washes.

Thanks Sherman. I will experiment with that and see how it turns out.

Thanks again for the advice.