AMMO by MIG Streaking Effects - Solvent Based Paint for Modelling
Color: Streaking Grime for Panzer Grey

From the Manufacturer:

Dark colored streaking effect specifically designed to be used over dark grey surfaces. Also suitable for other effects such as add chromatic richness to any piece or surface. Apply lines from the upper part of plate and then fade with a clean brush moist with Enamel Thinner.