Here's another picture from that era, of customers in standing in line outside, showing the street cars and the view across the street. I'm guessing the volume of people means that there was war-time rationing going on. This triptych from 1923 may show a glimpse of the sign, and here's the store with a new paint job in 1948.
Here's a Witt's ad from a 1901 Minneapolis Journal that's just too cool of an interweb find not to share. Anyone want 5 pounds of butter for $1? Going back even earlier, I have to wonder whether the store was an outgrowth of Witt's stockyard and slaughterhouse, which was established in Crystal Lake (now Crystal) in 1879.
This rather random website may explain the over-painted "L" word in that it describes someone with the last name "Lash" as having been a baker at Witt's. I've not yet been able to find what became of Witt's, but I have to run, so I will leave with the speculation that perhaps Mr. Lash took over for the Witt family and repainted the sign.
Finally, here's the fourth Commutator Foundry sign that I missed the first time around: