I rinsed my tobacco leaves after cutting / before drying, but I dunno how common that is in industrial farming. I've just grown a few plants as a hobbyist interest, advised by someone who helped grow tobacco 50yr ago, specifically for "plug" chewing tobacco. That's a bit different than the bulk of production even then.

Anyways my leaves were covered with a fuzz of (dead) gnats that needed washing off. My advisor says thats normal in moisture like mine.

"Washed" = soaped and waxed and repainted like commercial vegetables; then no. It all goes in a big grinder anyway.