I wonder if the Polish government even recognized her giving up her Polish passport and declaring or renouncing
If she only declared to the US authorities, then she's still a Polish citizen and can simply come to Poland and apply for an ID card (dowod osobisty) here. In this case, it's a formality and should be in her hand within a couple of weeks.
If she did renounce it formally to the PRL authorities, then it's more complicated - but my feeling is that as the daughter of a Polish citizen, she should be able to reclaim it rather easily too.
As I've said before - I'm not sure that Poland will even issue a visa, especially given the law that anyone that can be claimed as a Polish national must enter/exit on Polish documents.
I'm glad to see you find advice from Delph useful but he has no clue since he is neither Polish nor American and has not encountered any of these issues before.
The issue is clear cut - either she has Polish citizenship or she doesn't. You don't need to be Polish or American to figure this out - in fact, Polish citizenship law is really rather simple.
US allows dual citizenship
It doesn't permit it, but it doesn't ban it either. The legal situation is rather vague - which is why foreign nationals must make a declaration of renouncation to the American authorities.
If your mother in fact petitioned the Polish gov. to do that, then she is not a Polish citizen.
But anyone who can be claimed as a Polish citizen can very easily reclaim any citizenship unless they're affected by the various nationality laws - and this woman clearly isn't.
The town hall in Lodz said as long as I had proof I was out of Poland (receipt from a hotel in another country with my name and date on it, ex. Czech Republic, Germany) that would reset the 90 days.
Hahahaa. That's why they work in the town hall and not for the border guards.
You cannot *reset* the 90 days by any other means than by staying outside of the Schengen zone. You've got 90 days in every 180 days - use them wisely!