Essential weathering wash
The dark yellow wash does as advertised, ads realistic effects, mainly by contrast, especially with vehicles painted with colors of yellowish tones. Of course you can try it with models with other colors, for example I use it to paint vehicle wheels, and it gives an effect of having been used on land. In my opinion, this wash its one of the essentials in the weathering world.
Recommended
AK Interactive washes perform great as do others, the big plus to their use is the purposed tints that are paired with an intended base color. With paired colors, your recessed and shadowed areas look just that, and do not cause the stark contrasts of a black line drawing on white drafting paper.