Have a look at a custom filter for Substance Designer, Painter, and Alchemist by Ronan Mahon that will let you add fully procedural dirt and filth to any material for a fast and beautiful result that is easily customized. You will be able to get infinite variation quickly using automatic smart blends.
Features:
Responsive and easy to use
Automatic SmartBlending with any material in your scene
19 different customizable procedural masks or use your own input
35 ready to use Material Presets
Build your own material using the exposed parameters or even use an existing material from your library
Paint directly into Filther to customize it without the use of extra masks
Technical Details:
Includes SBS, SBSAR, and SmartMaterial
Fully procedural and with scaling resolution and detail – SBSAR is 96KB in size
SmartBlending auto samples your scene & utilizes the best input source it can find for blends
Over 40 exposed parameters and with random seed control
UV control and multi-input Triplanar projection
Direct painting without using masks to tweak the final result (add, remove, reveal)
Responsive – SubstancePlayer reports 50-60ms @2048 res with a regular setup, 120-170ms @2048 when enabling every channel and creating complex blends.
BaseColor, Normal, Roughness, Metallic, SSS, CustomFilth and CustomMask channels