Marriott, Hilton and other big hotel companies are used to competing on price or perks. Now they are competing on cleanliness.

From masked clerks at the front desk to shuttered buffets, hotels are making visible changes in the wake of the pandemic. Signage will tout new cleaning regimens: Red Roof Inns promise "RediClean," while Hilton boasts of "CleanStay with Lysol."

Hotels are still mostly empty; in the U.S., occupancy stood at 37% the week ending May 30, down 43% from the same period a year ago, according to STR, a data and consulting firm. But leisure travel is starting to pick up, and hotels see cleaning standards as a way to soothe jittery guests — and possibly win back business from rivals like home-sharing companies like Airbnb.

"I think, more than ever, customers are going to be looking for that seal of approval," said Phil Cordell, Hilton's head of global new brand development, who is leading the group developing the company's new cleaning standards.

Some hotel brands are more stringent than others, says Larry Yu, a professor of hospitality management at George Washington University. He notes that Accor Hotels, a French company, has developed accreditation standards that its hotels must meet in order to reopen.

But Yu said enhanced cleaning is happening everywhere.

"Everybody is doing it, because it is now expected by consumers," he said.

Guests are already seeing differences. David Whitesock, the chief innovation officer for Face It Together, an addiction counseling company, moved from Denver to upstate New York over Memorial Day weekend. He stayed at Marriott hotels in Iowa and Ohio along the way.

There were some oddities. Police tape separated him from the front desk in Iowa, and the hotel gave him a key card even though he would have preferred to unlock his room door using Marriott's app. Whitesock brought his own food, but noticed prepackaged breakfasts laid out where buffets used to be.

But he said his rooms looked, felt and smelled cleaner than they used to. All the guests wore masks and respectfully kept their distance, he said.

"I felt like it was a safe place to be, that they had done the best that they possibly could given the circumstances," Whitesock said. "A lot of it comes down to, do you trust the hotels and the people who you are going to come into contact with there?"

Despite hotels' precautions, however, visiting them is still risky, said Dr. Albert Ko, a professor of epidemiology and medicine at the Yale School of Public Health. Hotels can bring together travelers from states or countries where transmission rates are higher, for example, and many carriers may not be showing symptoms.

"That's the kind of thing we're worried about in terms of public health," he said. "Those settings can be the cause of outbreaks."

Hilton and other companies have called in experts to develop new standards. Marriott and IHG — the parent company of Holiday Inn — are working with EcoLab, which makes industrial cleaning products. IHG is also getting advice from the Cleveland Clinic. Hilton has partnered with the Mayo Clinic. Hyatt is working with ISSA, a global cleaning industry association.

Hotels walked through the guest experience and made changes at every touch point. Hilton's hotel shuttles will be disinfected hourly and passengers will have access to wipes. MGM Resorts, which is reopening four Las Vegas hotels on June 4, will ask restaurant guests to view digital menus on their own phones.

Changes vary by hotel. Guests may find lobby furniture moved further apart or hand sanitizer stations next to elevator keys. Shared coffee stations are gone. DoubleTree still offers warm chocolate chip cookies, but only upon request.

Inside the rooms, surfaces like TV remotes and light switches will get an extra cleaning. Best Western is getting rid of decorative pillows, pens and other unnecessary items. Red Roof is telling staff to bag up dirty sheets inside its rooms, to limit spread of disease. Once a room is cleaned and disinfected, Hilton will put a sticker on the door so guests know no one has been inside.

Ko said in addition to disinfecting surfaces, hotels might want to consider moving dining outside, where the risk of transmission is lower, or limiting capacity in tight spaces like elevators. Marriott's plan includes limiting capacity in restaurants and gyms and ensuring people are distanced in elevator lines.

Cordell said Hilton plans to keep pools and fitness centers open and clean them regularly.

"Fitness and wellness is so fundamental to the guests getting back in their routine," he said.

Hotels are experimenting with new technology. Marriott and others are using electrostatic sprayers to spritz lobbies with disinfectant. Many hotel brands are also encouraging guests to access their rooms using their mobile phones. Hilton says 4,800 of its 6,100 hotels have that capability so far. Marriott offers keyless check-in in 3,200 hotels.

Airbnb CEO Brian Chesky thinks guests will prefer separate homes to hotels filled with people. Airbnb — which is also working with EcoLab and former U.S. Surgeon General Dr. Vivek Murthy — will continue to upgrade its cleaning protocols, he said.

"Health and cleanliness are going to be one of our biggest focuses," he said.

But Yu said hotel chains can ensure franchisees are complying through their normal auditing process. That will be a challenge for Airbnb, he said, which has developed its own cleaning standards but may have more trouble ensuring that hosts comply.