So, is the influence from what you sold them to what's on the runways obvious to you?
M: I could tell you stories--and I won't. [Laughs] Sometimes they don't even change a stitch. Not one stitch. And a dress that they would buy for $175 will end up in the pages of Vogue for $6,000 and it's the exact same dress but with fabrics and workmanship that isn't as good, but it has their name on it.

Does that annoy you?
M: It does, but there really isn't anything I can do about it. So it's best just to be grateful for the business.

But you didn't patent the process?
M: We were very young.
J: They're certain things you can't patent. It was an accidental chemical reaction that we used for something, and it just did it.

So, everything in your store has been cleaned? How do you clean your clothes?
M: Jack has a degree in dry-cleaning. We're a perfectly green industry, and nothing goes out on the floor until it's absolutely perfect and clean.

Any favorite celebrity sightings?
M: Bruce Willis and his daughters are the nicest people. His kids are lovely—really down to earth.

You had a huge space in Union Square until about five years ago. Why did you leave?
M: Oh, the Batcave! It was 3 floors, 12,000 square feet. Max Brenner [the chocolate restaurant] is there now. The landlord wanted to raise our rent to a million dollars a year.

Cheap Jack's is located at 303 Fifth Avenue, near 31st Street.

Previously: Five minutes with collectible clothing guru Shannon Hoey of vintage shop New York Vintage.