I think they wash Hákarl before packaging it while Surströmming is still fermenting in the can until opened. The right way to open Surströmming is to submerge

I think they wash Hákarl before packaging it while Surströmming is still fermenting in the can until opened. The right way to open Surströmming is to submerge the can in water and wash the fish before serve. Much less smell.