I'm guessing that the results were much the same as I experienced with one of my first authentic, blown in mold, antique bottles that I found by deliberate searching in the woods near Riley Lake, east of Arlington, WA. A 1910 plat book from the Everett Public Library had provided clues on where to search near a ten-acre parcel my folks owned out that way. In the woods adjacent a property line, I found a small trash deposit almost completely obscured by moss and accumulated forest duff. I was so thrilled to unearth a square, amber bitters even though it was a slick.Also boiled a couple bottles and quickly found out why we shouldn't do that.
One of the earlier variants of Dr Kilmer's "Swamp Root" came to light for the first time in at least seventy years (my find was in 1970). I wiped the bottle with my gloved hands in order to admire the old embossed trademark that included the kidney-shaped, debossed panel, then laid the bottle upon a nearby patch of snow. (I was thinking what a nice soft and clean cradle the snow provided for my treasure.)
I went back to scratching through crumbled tin cans that comprised the majority of the trash deposit that was only inches deep. After I uncovered another bottle, I turned to place it on the snow cushion beside the Dr Kilmer's only to find my treasured patent medicine bottle lying in three pieces!
Until that moment, it had never occurred to me that the temperature in the debris would differ enough from the melting snow's 32 degrees F that the rapid chilling would crack my prize, let alone leave it in pieces! Such tough lessons are remembered well.