SALT LAKE CITY — A series of graffiti-like paintings on rocks in National Parks across the West set off a furor on social media this month, angering people who say they desecrated some of the nation's most famously picturesque landscapes. They've also created a headache for park managers who have the delicate task of cleaning up the sites without causing further damage.

It won't be easy to get rid of the paintings, which were posted on Instagram and Tumblr and then picked up by hiking blogs. Sandblasting and some chemical strippers can cause even more damage to irreplaceable natural features, especially if graffiti is near ancient rock art.

See also: Authorities Investigating Blogger for Painting on Rocks in National Parks

In some cases, workers use plastic kitchen spatulas to painstakingly scrape off paint. Workers test different strippers to figure out which will loosen the material without damaging rock, then rinse it off with lots of low-pressure hot water, gently scraping each layer away with the spatula, said National Parks spokesman Jason Olson.

Instagram Artist #CaseyNocket may face felony charges after leaving her mark in National parks http://t.co/Xbc0TLvMZE pic.twitter.com/Nkz26TFUjn — Bryan Johnson (@BryanJohnson__) October 22, 2014

"They will repeat that as often as it takes until they remove all the paint or until they can't remove any more," he said. He said Friday he didn't know how much it might cost to go remove the paint in eight parks across California, Colorado, Utah and Oregon. One colorful painting of a woman with blue hair at Crater Lake National Park is already covered in ice and snow and workers might not be able to reach it until next summer.

Casey Nocket, the 21-year-old suspect identified by the park service this week, allegedly used acrylic paint and signed with the handle "creepytings." Attempts to reach Nocket were unsuccessful. A phone listing for her was disconnected and her social media accounts have been shut down or made private.

The case became the subject of widespread social media outrage from people reacting to paintings inserted into the landscape and documented as an apparent artistic expression. The Modern Hiker blog identified Nocket from her social posts.

This makes my wild outdoors heart sad http://t.co/MzHHa87GbR pic.twitter.com/NOYELv3baR — Ashley Braun (@ashleybraun) October 23, 2014

The National Park Service said this week they've found paintings in Yosemite, Death Valley and Joshua Tree in California; Crater Lake in Oregon; Zion National Park and Canyonlands in Utah; and Rocky Mountain in Colorado, where Colorado National Monument was also tagged.

Instagrammers had identified several paintings in different parks, allegedly left by Nocket.

Zion National Park is home to red-rock bluffs, sweeping canyons — and now a backpack-sized drawing of a woman smoking on a rock near a trail named for emerald-colored pools of water.

It's not the first time rangers have had to clean up, though paint is an unusual choice for vandals there.

Supervisory ranger Ray O'Neil said minor graffiti is scratched onto rock every day. Rangers carry nylon bristle brushes and water to brush it off as they see it.

At Joshua Tree in California, the park service has graffiti they think is from Nocket to deal with, and also a project to clean up the historic Barker Dam, which is nearly covered with scratched-on graffiti.

"Even though people know they shouldn't do it, as soon as someone else has done they just jump right on board," said cultural resources chief Jason Theuer. Sandblasting the structure originally built in 1902 to provide water for cattle could cause microscopic cracks, damaging the surface and creating a home for water and bacteria that cause more damage. Instead, they're using paint to fill it in.

Rangers deal with graffiti nearly weekly there, and the most difficult material to clean off is metallic spray paint. In some cases, graffiti near ancient petroglyphs or pictographs is nearly impossible to remove and rangers have to leave it.

Even if the rock art itself isn't damaged, the soil itself can contain other essential archaeological clues like microfossils that can be damaged by cleanup chemicals.

That's why officials say people shouldn't remove images themselves if they see them. Instead, they're hoping that the high-profile case raises awareness about an issue that's all too common in the parks.

"It's a basic, fundamental underlying facet of human nature is to sort of leave our mark," said Theuer. "Our national parks are not the place for it."

Additional reporting by Mashable