ABC News' Matt Hosford Reports:
On Tuesday the National Mall was full of them.
Whether clutched snugly in palms, stuffed into pockets or crammed into boots, hand warmers were as much a part of the inauguration of Barack Obama as the record crowd.
You couldn't go far without stepping over a torn-open wrapper and the ground was littered with the bodies of hand warmers that had fallen in the battle against frigid temperatures.
Hand warmers even made an appearance on ABC's inaugural coverage. ABC News' Deborah Roberts told Charlie Gibson the crowd was getting by on a combination of determination and hand warmers, pulling one out of her glove with a flourish for effect.
Later in an off-camera moment, Roberts gracefully removed her boots and put toe warmers on her socks. Strangers in the crowd held her up to do it. When it came to warmers, we were all in it together. It was that cold.
It wasn't just on the Mall. As the inaugural parade marched by, First Lady Michelle Obama was spotted slipping hand warmers into her gloves in the reviewing stand outside the White House.
At least one Secret Service agent manning one of the security checkpoints surrounding the Mall was using hand warmers. She rebuffed a certain ABC News producer's offer of all the toe warmers she wanted in exchange for help in navigating the complex maze of checkpoints.
It was heartening, but not necessarily warming, to know that integrity trumped hand warmers, at least in this case.
That didn't mean people weren't trying to make a buck on them.
Vendors worked the crowd hawking two-packs of hand warmers, and kiosks outside of the Mall were selling them straight out of the box. One person, upon seeing my pack of hand warmers, told me they were worth a hundred dollars.
She was kidding, I think.
So how do these little angels of heat work?
It’s a simple chemical reaction, said Danny Garvey, who has 15 years of experience selling hand warmers at Georgia-based Heatmax, Inc., maker of HotHands.
Inside each hand warmer is a mixture of iron powder, water, salt, activated charcoal and vermiculite. When you tear open the package a chemical reaction is triggered.
Note well: Tearing the package open is best done BEFORE your fingers are frozen. Water inside the package mixes with the iron powder and causes it to rust at such a high rate that it produces heat.
Garvey said if used properly, that is put inside your gloves, hand warmers should last 8 to 10 hours. So simple even a TV producer can do it.
"There's no telling how much product we sold," said Garvey, adding that Heatmax, just one of the companies that makes hand warmers, saw great demand for its products leading up to the inauguration. "It’s a great thing to have a USA-made product used in the inauguration."
Garvey insists his product is biodegradable, but said he would prefer that people dispose of them properly. In all, 120 tons of garbage were collected from the National Mall and the surrounding streets of Washington, DC following the inauguration. How much of that was hand warmers is hard to say.
Nancee Lyons, a spokeswoman for the DC Department of Public Works, said she definitely noticed the number of hand warmer wrappers on the ground, but, "for our crews, trash is trash."