That info is wrong, the jar has the M & N in MASON, the vents for the others letters were most likely clogged and the molten glass for the ASO never made it into the cutouts for the embossing. The jar isn't anything special really, more of a novelty because of the clogged vent holes, that might give a little more value to a jar collector, but only a few bucks worth IMHO...That's a nice one! It is not an error but a very early "Ball" jar that did not use the word mason. CA 1910.
That info is wrong, the jar has the M & N in MASON, the vents for the others letters were most likely clogged and the molten glass for the ASO never made it into the cutouts for the embossing. The jar isn't anything special really, more of a novelty because of the clogged vent holes, that might give a little more value to a jar collector, but only a few bucks worth IMHO...
Often referred to as a 3 "L" jar because of the loop in the line that returns under the word Ball, it dates 1896-1910...
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I see the residue from M&N now. I have one just like it, and thought they were made that way. Must be a pretty common error.