These products should be applied with a dampened brush in layers until you reach a tone that matches your references.
Referring to the photos I had of the Bradley with ERA blocks, there was grime that would seep out from the seams that separate the blocks. To replicate this I used A.K Interactive Streaking Grime for D.A.K vehicles. Placing small amounts of the product in the seams of the blocks, it was left to dry for five minutes at which point it was stumped with a damp brush until the effect I was looking for was achieved.
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