SOLVED. 1950's-70's Sci-Fi retelling of "The Pied Piper of Hamelin." [s]

[Rosa]

My dad told me about a story he read in an sf anthology when he was 12 or so —early/mid 70's.
Earth has rats—it's quite a problem—and aliens come down. They say they can help Earthlings with this plague, because they've done it before. The Pied Piper of Hamelin was actually one of them. This time, as payment, the aliens want priceless works of art: Leonardo da Vincis, Michelangelos, etc. The Earthlings agree, and the aliens get rid of the rats. But then Earth leaders try to pay them with lower-tier, 20th-century art by masters like Norman Rockwell and Andy Warhol. (Opinions are not necessarily my own. Don't know if it was either of those artists specifically.) The aliens are not pleased.
I don't know the ending, but presumably the aliens make like the Pied Piper and take something far more valuable as revenge.

[Ergative]

I can't help you, but I'm snickering up my sleeve at the inherent value judgment the author put into this work. "Your so-called 'modern art' is such crap that even *aliens* won't take it! Kids these days with their 'statements' and 'societal commentary'. Why, in my day we knew quality and revered the old masters andgrumblegrumblegrr . . . "

I quite like Normal Rockwell, myself!

[Rosa]

Yeah, but is it priceless?

[Ayshe]

I found The Hardest Bargain but some details are different, there's more detailed review here: https://hubpages.com/literature/Art-H...

[Rosa]

Fantastic find, Ayshe! That's got to be the one. However did you find it?

[Ayshe]

I searched for rats paintings "pied piper " "science fiction" in Google books and one of the results snippets was the alien's name(?): Foma, searching further with that helped.

[Lobstergirl, au gratin]

Are you ready to call this solved?

[Rosa]

Not quite yet. I'm going to give him the anthology Beyond Belief for Hanukkah and wait for the cry of recognition.

[Rosa]

Happy Hanukkah! He was thrilled! Thank you again, Ayshe.

[Rosa]

Ergative, it actually wasn't quite like I described it. The President's advisor substitutes paintings with nicer, prettier subject matter than the paintings the aliens requested; they're no newer than the promised paintings. It's quite a good lesson in art history, actually. In the blog post Ayshe linked to, the blogger has collected images of almost all the paintings mentioned (one apparently doesn't exist). If you're interested, the story can be read here.