Over the years I’ve heard countless explanations from various aldermen of what TIFs are and how they work.

I’ve heard aldermen Berny Stone and Ed Burke claim that TIFs don’t raise property taxes, even though they obviously do. I’ve heard former alderman Patrick O’Connor say that the operating details of TIFs are just too complicated for ordinary people to understand, so why bother explaining. And I’ve heard everyone from former alderman Ted Matlack to alderman Pat Levar get lost in the netherworld of tax increment financing until all eyes glazed over.

But yesterday up on the northwest side I heard something unique. Speaking before a group of residents who wanted his opinion about a TIF-funded school proposed for their community, 38th Ward aldermen Tom Allen told something close to the truth. TIFs, he said, are “slush funds” created by raising the property tax.

Why is the city using them to build new schools? someone in the audience asked.

Because it’s embarrassing to keep doling them out to developers, he explained. “We’ve got this little slush fund called the TIFs just sitting there. We [the aldermen] started convincing the [Daley] administration to have to cut loose this money.”

Maybe Allen’s gearing up to take the bold step of voting against future TIF districts, which require City Council approval.

At the same meeting Allen took a survey, asking his listeners whether they supported putting the Children’s Museum in Grant Park.

The audience erupted with a chorus of nos, firing off a barrage of questions and comments: Why put it there? How much stuff are they going to cram in that park? They should put it somewhere that really needs it.

This meeting was being held in the basement of a church near Cicero and Addison, mind you. So Mayor Daley can’t accuse these people of being high-rise dwellers who want to keep black children out of their neighborhood.

“When Mayor Daley gets mad at me, will you stick up for me?” asked Allen, strongly suggesting that he planned to vote against the museum.

“Will you stick up for us?” one resident responded.

Ah, Chicago, city of deals.