Ha ha! I originally thought the idea of throwing sour-whey onto the fire was so ridiculous that it couldn’t possibly be right (they would be more likely to pee on it than waste their whey ) and ended up inventing even more ridiculous explanations, thus ending up with whey (if not egg) on my face !
> en þeir, er inni váru, báru í vatn ok sýru í eldinn ok
> slökktu svá sem þeir máttu.carried water and sour whey to the fire and quenched it as
> smeered water and sour whey in the fire and extinguished
> so as they were able.
>carried in water and sprinkled (sprayed) [it] (variant spelling of
> <söru>, past tense of <sá>, Z3?) into the-fire, and
> extinguished such as they could.