1). I've been looking into gas bleaching atm. You could bleach the fog back with bromide fumes or HBr gas possibly (before shooting). Should remove built up fog (metallic silver back to halide) without washing things out. Haven't tried it yet though, so no guarantees.
Possibly even expos it to SO2 gas in a tank to convert the fog to silver sulphate? Not sure on any of it, just ideas.