Fourth-grader has fun selling slippery stuff known as slime

but also selling it — to her friends, door-to-door in her neighborhood and online through her “slimeyomg” Etsy shop, where she offers varieties such as scented gingerbread slime, birthday cake slime and lilac-scented cream cheese slime (all nonedible).

The start of the current slime craze has been hard to pinpoint. Leen Nsouli, who tracks sales of office supplies for the NPD Group, a New York-based market research company, wonders if some of it might have been kicked off by the “Ghostbusters” reboot last summer. Whatever the initial impulse, she said, slime has taken off on social media, noting that there are more than 2 million #slime posts on Instagram.

How-to slime videos are in abundance on YouTube, including one with more than 2.5 million views from “Dance Moms” star and former Murrysville resident Mackenzie Ziegler (Maddie’s little sister).

The ingredients in a basic slime recipe are glue, borax and water, with optional additives such as shaving cream, lotion or food coloring to change its appearance, smell or consistency. Slime is a “non-Newtonian fluid” formed when the long polymer chains of molecules in glue combine with borax, creating “bonds between the chains that lock them up so they can’t bend as much,” said Katie Brunecz of the Carnegie Science Center, which hosted about 200 kids for a “Slime Sleepover” last weekend.

In Moon, sisters Peyton and Emma Perry demonstrate the process in less than 5 minutes on their kitchen island, mixing glue with a borax and water solution, adding lotion and glitter, and kneading the goopy slime with their fingers until it begins to hold together.

Their first attempt at making slime in December was a failure, possibly because they tried to use regular laundry detergent instead of borax. But in January, while her mom and 13year-old Emma were out at the Twenty One Pilots concert that Peyton was deemed too young to attend, the 10year-old tried again at her grandmother’s house, with much more success. And she was hooked.

“It was the funnest thing I ever felt,” she said, while stretching and popping a white “stretchy slime.”

Once Peyton got the hang of it, she began selling slime to her classmates at Moon Area Middle School. And that got her older sister’s attention.

“At first, she was making it on her own,” said Emma. “Then I figured out she was actually making money.”

The two have made about $70 in profit so far, brainstorming ways to make their product stand out from that of the other kids at their school also selling slime. They have bought fancy cases for their $5 slime ($2 will get you slime in a plastic bag) and embellishments like googly eyes for their “monster slime,” red glitter for their top-selling “Valentine’s slime” and special luminescent paint for their “glow-in-the-dark slime.”

Emma often markets their slime on Snapchat. “It’s fully customizable,” she said. “If you want red slime with glitter we will do that for you.”

“Business-wise, they’ve learned a lot,” said their mother, Debby Perry, a publisher of websites including Macaroni Kid. “And they’re working together.”

Money from the slime fad isn’t just going into the pockets of grade-schoolers.

Sales of liquid Elmer’s glue, widely regarded as the best glue for slime production, more than doubled in retail stores in the last four weeks of 2016 compared to the same period the previous year, said Caitlin Watkins, a company spokeswoman. Sales of all types of glue were up nearly 40 percent in the first three weeks of February compared to those weeks last year, said Ms. Nsouli of the NPD Group.

That demand has made glue hard to find on store shelves. Giant Eagle, for example, is recommending that customers seeking to purchase glue call ahead to ensure availability. “Like many retailers, we have recently noticed increased demand for glue that has impacted the overall availability of the product,” said company spokesman Dick Roberts.

Peyton recounted going from Walmart to Walgreens to CVS in search of glue, with little success. She finally was able to stock up at Kmart, though she thought twice before letting a reporter in on that secret. “No one had hit them yet,” she said. “It was like glue heaven.”

Elmer’s has increased production of its most popular slime-making glues, while other retailers also try to capitalize on the phenomenon. “We’ve Got You Covered ... In SLIME!” tweeted Office Depot’s corporate account on Thursday. Michaels has installed “Slime Headquarters” on aisle endcaps, with displays sporting glue and slime mixins like beads and glitter.

All that slime has become a distraction in some schools, such as Ross Elementary School in the North Hills, where the principal noted the popularity of it among “kids with an entrepreneurial spirit” in an email newsletter asking parents to keep it at home.

Though there have been scattered concerns about the toxicity of borax, the medical director of the Pittsburgh Poison Center said that hasn’t been much of an issue here. “We don’t see a lot of patients or kids presenting with adverse effects,” said Michael Lynch, noting that it shouldn’t be inhaled or ingested. “It’s not a common toxic exposure.”

Brooke, the Peters fourthgrader, first tried to make slime this fall after she heard about it from a friend of her 12-year-old sister. That effort was unsuccessful, also perhaps for lack of borax, but Brooke kept at it, finding success with her own recipe developed just by feel.

“I showed all my friends and they were like, ‘Make me some, I need some,’ ” she said.

And so her Peters slime factory began. Brooke whips up a batch of slime nearly every day, in a designated spot in her basement that her parents directed her to after they were tired of seeing trails of slime in bathrooms, and after a failed experiment making an entire gallon at once did a number on the dining room carpet.

When she started selling it, she came up with the name slimeyomg and downloaded an app to make herself a logo. Her father, John Koutsogiani, helped her calculate costs to set a slime price of $1 per ounce. She’s been donating her profits to the United Way, in part because her parents pay for her slime supplies, which include eye shadow for a tint with a pearl sheen, Japanese clay for her thick “butter slime” and foaming hand lotions for scent.

As for the longevity of the slime craze, Ms. Nsouli wonders if the popularity of slime may wane as the weather gets warmer and outdoor activities take precedence.

As for the Perry sisters in Moon, the end of slime is hard for Peyton to imagine. “Nooooo,” she said. “I love it.”

To that, her 13-year-old sister shrugged. She’ll be into slime, Emma said, “as long as we keep selling.”