Like any smart brand, Hermès knows a lot about its customers, and one of the things it knows for sure is that they are particularly loyal. They are passionate. They are a little bit obsessed. And so on Friday, when it opened a pop-up shop in CityCenterDC where customers can bring in their vintage Hermès scarves to have them dip-dyed, no one was the least bit surprised that there were people lined up waiting for the glass doors to open despite an impending monsoon. They came with their beloved scarves folded into clear plastic zip-top bags. Some of these scarves they’d had for a decade or longer. Some they rarely wore any more. But they’d held on to them because, well, they are Hermès and that is what one does.

Among the first to arrive was Shahn Rosler, an unassuming woman with a dark ponytail who’d taken the train down from New Jersey that morning. She’d brought 32 scarves with her, and she was standing patiently at a large worktable while the “dye experts,” women in white coveralls and work shirts, sorted through them and prepared them to be dyed.

This process, which is free, is a cut above a do-it-yourself tie-dye project that one might attempt in a bathtub. This is not Coachella on the Potomac. A once-empty store front facing H Street NW has been remade into Hermèsmatic, which is akin to a large orange laundromat bedecked with the French company’s logo. Outside, an Hermès bicycle and its attached baskets have been draped in pre-dyed scarves. Sitting on that bicycle is a man in a white polo shirt and jeans whose job is essentially to be handsome, which he does quite well. Inside, four full-size orange washing machines line one wall. The dye experts inspect each scarf to make sure that it’s a good candidate. They rejected two of Rosler’s scarves: one because it was pleated — and the pleats would be lost in the wash — and another because it was chiffon, and only silk twill scarves are accepted.

Customers have a choice of hues: fuchsia, green or blue. Rosler was going to experiment with all three colors, but she wasn’t dyeing blind, because the dye ladies, who have been trained by Hermès and have some previous experience in textiles or chemistry, provide a fairly specific assessment of what the finished product might look like after it has been washed, dyed and dried — a process that takes about 48 hours.

The company hosted a similar dye extravaganza in New York in June and will bring similar events to Nashville and Los Angeles in the fall. For Rosler, Washington is a long way to come for a dye job. But she missed the pop-up in New York and so here she is, fresh off Amtrak.

Some might call Rosler obsessed with Hermès scarves; others might simply say that she is a fan, or even an investor. She owns about 300 scarves, some of which date back to the 1980s. “They’re classic, they’re beautiful, they’re wearable works of art,” she explains. A new Hermès scarf is about $395 and so if you do the math, over the years, Rosler has spent in the vicinity of $120,000 on scarves. (So it’s probably best if you don’t do the math.) The dollar figure does not seem to concern her family. The sheer volume is a different story. “When I had to carry them all down from her room to the dining room, that was worrisome,” says her loyal daughter-in-law Jaclyn, who accompanied Rosler to Washington and was busy filling out scarf paperwork.

Before the washing machines begin to whir, let’s take a moment to consider the subtext of Hermèsmatic. Hermès silk scarves, which are hand-rolled and hand-stitched, have pleasantly pleasing patterns, and a quick look at eBay and 1stdibs suggests that they tend to hold more of their value than other brands. The company encourages its customers to collect them by regularly releasing new prints and marketing the scarves with the mystique of history and the allure of France, where they are produced. For a brand that sells a simple calfskin credit card sleeve for $500, the scarves — colorful, distinctive, traditional — are alluring to those of more modest means, yet they remain aspirational. And by dyeing them gratis, the company drives home the idea that the scarves are not a disposable commodity. No, no. They are an heirloom. You refurbish them. And pass them down.

All that might make owners a bit hesitant to subject their investment, their inheritance, to the vagaries of dye. Might Rosler regret having scarves dyed fuchsia or jungle green? “When you have 300 [scarves], what’s to regret?” she says with a shrug. Dyeing them, she says, will make them one-of-a-kind.

The results are, in fact, striking. The process doesn’t so much glaze them in a flat coat of color as it alters the existing colors, intensifying some shades or, for example, turning red to purple or beige to deep blue. It can cover up a stain or transform the chartreuse in a print called “Rose de Compas” into something closer to chocolate brown if chartreuse is just not your thing. And Leah Neth of Alexandria does not like chartreuse.

“We should throw caution to the wind and [dye it] pink?” says Neth to her husband, Ron, as she gazes at the offending scarf spread out on the examination table.

“Yes,” says Ron.

Leah: “Is that what you’re thinking?”

Ron: “Yes.”

Leah is holding a cobalt blue Birkin. It is a lovely bag. Ron is holding more scarves. He pulls them one by one from a little plastic bag, and Tessa Morehouse, the dye expert with the Hermès-orange hair, unfolds them for inspection. Ron has salt-and-pepper hair, a genial demeanor and a good-natured willingness to talk about dyeing scarves. Leah owns about 30 Hermès scarves. She’s brought in eight, including several from friends in Texas and Massachusetts who were organized enough to send Leah their scarves in advance and deputized her to get them dyed.

Like everyone else who brings in a scarf, she will return two days later to retrieve them. Rosler planned to take the train back from New Jersey on Sunday with her husband. They’d make a day of it in the nation’s capital. And maybe she’d buy a new scarf.

Hermèsmatic is open until Aug. 5.