Stillwater Mayor Ted Kozlowski woke up Friday morning with one question on his mind: How do you make 25,000 tons of ice disappear quickly?

A humongous ice cavern built on the city’s riverfront will close Saturday, leaving lots of icy ruins.

“There’s only 30 days before we’re boating again on the St. Croix,” Kozlowski said, adding that it would be nice to have the ice in the riverfront park gone before then.

Last year, the ice castle meltdown relied solely on Mother Nature, which means people were still walking around ice chunks in April.

So in the name of science and humor, Kozlowski issued a community challenge in a Facebook post: “Seeking ideas to quickly melt a giant ice castle. It must be environmentally friendly, as this ice castle is located on the bank of a beautiful river. No salt, chemicals, etc. Process must not damage the grass or park structures.”

The ideas rolled in: Dragons, flamethrowers, electric blankets, a multitude of hair dryers, a giant magnifying glass. How about arming folks with chisels and glasses of whiskey? Or, shove it into the river and let it float down to Bayport? Covering it in dark coffee grounds would absorb the sun and provide a nice wake-up aroma to the riverfront.

Or, Kozlowski quipped, city crews could coat it in cupcake sprinkles and turn it into a giant snow cone.

Just musing about an accelerated ice castle take-down is providing a bit of community levity, Kozlowski acknowledged. But he also believes “a smart Minnesota scientist” might come up with an idea to outdo Mother Nature while turning the castle’s demise into a fun community event. “I know there’s chemistry and physics involved in this to do it the right way,” he said.

One of the more practical proposals, Kozlowski said, would be to call on the Stillwater and neighboring fire departments to blast down the castle with water while onlookers cheered.

That sounds like a good idea, but turns out it’s not practical or efficient, said Brent Christensen, founder of Ice Castles Inc., the Utah-based company that built the Stillwater ice cavern, along with three others across the United States and two in Canada. He’s been building ice castles for eight years and has tried a “myriad of different things,” including pressurized water, to speed the melt. “The amount of water [needed] would be more than what we used to grow the whole thing,” he said.

Beginning in December, crews spent four weeks growing and harvesting icicles and then spraying them with water to create a two- to three-story massive walk-through ice sculpture that included tunnels, passageways, ice slides, igloos and a fountain that were aglow in LED lights. The walls are 10 feet thick and the floor 4 to 5 feet thick in most places.

“The bottom line is that it’s massive,” Christensen said.

Once the castle is closed this weekend, crews will remove plumbing and as many embedded lights as possible, which sometimes requires cutting and boring into the ice, he said. Excavators will topple the structure to ensure it’s not a looming hazard with caves that people can climb into. “It will be a huge one-acre mound of ice,” Christensen said.

He’s tried salt and snow melt to speed up the melt, but it’s not good for the grass, he said. In the end, sun and spring rain may be the best ways to bring an ice castle down, he said.

Still, Kozlowski’s Facebook page is lighting up with even more ideas: a giant knitted castle cozy, laser beams, parabolic solar array using Mylar sheeting.

“We’ll always entertain new ideas,” Christensen said. “If they come up with an idea … that has merit and isn’t exorbitantly expensive, I’d love to try it.”

But sometimes, he said, “You just have to be patient and wait for the sun to do its job.”