how much is this money worth?

It is one of my favorite lines from The Simpsons.

Well, it is one of the hundreds of lines from the masterly scriptwriters of The Simpsons that I call my favorites.

Mr. Burns, the town billionaire and eccentric octogenarian, is in the post office mailing a letter: "I'd like to send this letter to the Prussian Consulate in Siam by aeromail. Am I too late for the 4:30 auto-gyro?"

I thought of Mr. Burns the other day when my church buddy Darleen gave me three large denomination notes. Not that Darleen reminded me of Mr. Burns. She doesn't. But the situation did.

When she moved to this area of Mexico, one of her friends told her that she and her husband had visited Mexico years ago and that they had a lot of pesos. Since they were not going to be using them, Darleen was the beneficiary of what appeared on its face to be an act not only of altruism, but true sacrifice.

It was a total of 10,050 pesos. At today's exchange rate that would be 504 US dollars -- and change. A nice gift.

But the three bills are worth 500 greenbacks only if you live in the world of Mr. Burns. The rest of us have moved on -- as has the Bank of Mexico.

If you have really good eyes, you can see the issue date on the notes. The 50-peso note with the familiar stern, blue visage of Benito Juárez was issued in 1981. The two 5000-peso notes featuring the Niños Héroes (who died defending the Castle of Chapultepec -- and the honor of Mexico -- on 13 September 1847 during the Mexican-American War) were issued in 1984.

A lot of pesos have come out of ATMs since the early 1980s -- including a monetary devaluation in 1993 followed by a financial crisis in 1994-1995. Mexico is now on its fifth series of banknotes since the monetary children of the 1980s were printed.

As a result of the devaluation and subsequent issue of new banknotes, the value of the three old notes is officially -- zero. As a matter of legal tender. A collector may put a small value on them -- or those of us who see banknotes as a form of art can value them as something other than mere lucre. But they will not buy you a cup of coffee.

Mr. Burns had another observation for a similar situation: "Ooh, don't poo-poo a nickel, Lisa. A nickel will buy you a steak and kidney pie, a cup of coffee, a slice of cheesecake and a newsreel... with enough change left over to ride the trolley from Battery Park to the polo grounds."

Acquaintances who work in restaurants, hotels, and shops tell me that some unwary tourists still attempt to pass these outdated notes to pay their bills. Usually it is just a matter of the tourist not knowing he is part of a Mr. Burns skit.

I know of only one exchange that was larded with evil intent. A customer at a restaurant in San Patricio Melaque told a young waiter that the only bill he had was a 10,000-peso note. If the waiter would break it for him from the restaurant till, he would let the waiter keep 1000 pesos for himself. The note was issued in 1982.

That con may have worked in one of Mexico's wealthy tourist cities like San Miguel de Allende. But, in San Patricio Melaque, the cash in the till would have been far short of 10,000 pesos.

When the waiter took the note to the restaurant manager, the customer-cum-con man turned himself into Jesse Owens and ran off without his note -- or paying his bill.

But I am now the proud owner of notes that were printed when I was but a lad enjoying his 30s. There are so many possibilities. I can appreciate them as art. Or remember them as a gift from Darleen. --

Or I could take them down to the local post office and ask Julio: "I'd like to send this letter to the Prussian Consulate in Siam by aeromail. Am I too late for the 4:30 auto-gyro?" And see if I could squeeze any more humor out of the gag.

I doubt Mr. Burns will ever die.