Plash progress...
Washed twice with detergent, tumble dry after each. Two more times with isopropyl alcohol, one more wash, then a final rinse. Then tumble dry again. It should go without saying, but do not dry after washing with alcohol... as it may catch on fire. Wash and rinse well.
Dyebath was three bottles of black, with two cups of salt. Left to sit, with occasional stirring, over three days. Rinse till the water runs clear. Let dry till barely damp, tumble dry.
Lightly sprayed with matte black Duplicolor Vinly/Fabric paint.
First coat of base armor color was worked in with a chip brush. Then two additional shades of gray were splattered in while the plash hung vertically.
I manipulated the brightness in-camera so I could see the different layers.