For this prompt at comment_fic:'Author's choice, any/any, they wear one item of the other's clothing for luck.' I kind of stretched the 'clothing' part by the end of it.
The first time Tony sees it is with Romanoff. She has to abandon her boots mid-mission and go the last few minutes in a pair of fuzzy, purple and black socks, and Tony isn't sure what to make of them. He'd always figured her for utilitarian footwear in a work situation; the kind with reliable quality and that you can buy in large amounts and which is too plain and everyday to be traced. She's really very practical if you get right down to it. But before he can ask they're back to dealing with the chemical manufacturing robotics set on the warpath by a madman intent on gassing Los Angeles with toxic fumes, and he forgets about it until later.
He's making himself a smoothie and she's reading something on a laptop when he thinks to ask her, "What was with those socks, by the way?" Carrot and mango? No, maybe carrot and banana...
"What socks?" He can hear the frown in her voice.
Carrot and apple. "At the plant, when you lost your boots. Your socks looked pretty unique." He adds a little mango and pineapple juice and a celery stalk, and blends it up. "You always struck me as a standard issue kind of person for something like socks."
Her reply is deadpan and matter-of-fact. "My taste in socks is unparalleled."
This is Romanoff-speak for 'you're not getting an answer to this question no matter how many ways you ask it', so he says, "Clearly," and sips from his smoothie. It's a little tart and bracing, but really not too bad.
A few days later he sees Barton lounging on the sectional playing Lovers in a Dangerous Spacetime with Wilson. ("This bear is on my very last nerve." "Up! Up!" "I am it's just—" "Shield.") Barton's feet are propped up on the coffee table, and he's wearing the same pair of socks.
Wilson is sporting a pair of faded, blue, too long, denim jeans as they suit up for an 'unnatural' sandstorm that's trying to obliterate Casablanca, Morocco. Tony eyes them and says, "Were you too embarrassed to return them?" Despite his quip, Tony can't help but note they're worn around the hems and faded here and there; not new, for sure. Probably a favorite pair.
Wilson scoffs at him. "You know I look good in these," he says, and flashes his teeth in a grin.
That night, Rogers comes into the great room and says, "I think we've got a laundry room gremlin."
Tony has had JARVIS clean the suit three times and there's still sand in it, thus he's decided now is the time to work on modifications to prevent this kind of issue. In between flipping through design changes on a tablet, he says, "Pepper made sure to get left sock insurance on those dryers, so just buy new ones and charge the team card."
"It's not my socks, it's my pants."
Tony frowns at Rogers over the edge of his tablet. Rogers makes a helpless gesture.
"Last month it was some khakis. This week, my old jeans."
"Can we agree that nothing you own is 'old' compared to you? Compared to Thor?"
Rogers gives him a tired look. "They're the first pair I got after I thawed out," he clarifies.
Tony flashes back to earlier that morning, before they all spent a few hours being sandblasted. "Might want to take it up with Wilson," he says, and goes back to his suit. The suit he is going to make sand- and dust-proof, because there is no way in Hell he's ever spending that much time getting sand out of his scalp again.
Rogers stares at him for almost a full minute before he quits the room.
With Thor it really shouldn't come as a surprise, since Meaningful Gestures are the kind of thing Thor does on a regular basis, particularly this sort. Yet Tony still double-takes when a bit of red and gold and black velvet peeks through the shoulder to hip gash on Thor's breastplate, so much so that Rhodey asks him what's wrong.
"Ah, nothing, we're good."
Rhodey's expression telegraphs 'you owe me an explanation', and they get back to helping Thor's battered, bloodied self into a seat on the Quinjet. After Thor's settled Rhodey coaxes his suit back outside to help with cleanup for as long as the armor can hold out.
Tony fingers the edge of the scarf—on closer inspection he sees it's a rose vine pattern in burnout style—and raises his eyebrows. Thor's just conscious enough to notice.
"It is one of Jane's," he says, and adjusts his position in the seat with a grimace. "For luck."
"Right." Tony peers through the tear in Thor's armor. "Well, it worked—the scarf's fine." That's amazing considering the amount of blood all over him, most of which is his own.
Thor huffs a breathy laugh and shuts his eyes. In another second he's holding perfectly still, one hand resting lightly on the hammer's handle, and Tony's suit registers the usual energy field building up. He checks to make sure Thor's strapped in securely, then goes to help Rhodey and Wilson with their efforts to salvage the remains of the Hydra cell's weaponry.
By the time they arrive back at the Tower Thor's mostly able to move on his own, but Bruce insists he do his next healing nap in the infirmary. He's more than a little concerned the odd weapons their foes were wielding aren't 'just' nasty spears and swords with vibrating blades. Thor acquiesces, maybe because he lacks the energy to argue with Bruce and Foster and Rogers (who's only a little better off than Thor, but you'd never know it by how gamely he rises to the challenge of getting Thor to rest).
Foster and Bruce help Thor out of his armor and into a set of sacrificial sweats. Some of the injuries are truly hair-curling, so Tony excuses himself to the lab across the hall and pulls up the mission data on a holotable. Of particular interest is the device that seems to have imbued the weapons with their phenomenal power level: a four foot diameter torus covered with alien script and made of an unidentifiable, dark blue metal which Thor used most of his energy knocking out.
Tony glances through the infirmary door after a few minutes and sees they've gotten Thor onto a bed with the hammer laying down next to him. Foster and Thor exchange a few words before Thor falls asleep. As soon as the regeneration field is in place the monitors show improvements in his vitals, which seems to appease Bruce.
Jane brushes some of Thor's hair away from his face and wraps the scarf around his neck. She and Bruce come into the lab, and she singles out the information tables for the weapons and their power source.
"Did you get them all?" she asks, her tone clipped and hard.
With a glance at Bruce, Tony says, "Yeah. We think so." Bruce nods in agreement.
"Good." She rearranges the imagery of the device so it's displayed in 3D, and they get started.
Tony has always assumed Bruce didn't carry anything sentimental with him. His wearing and carrying options are limited, and there's a good chance anything he has on him will just get destroyed. (In a lot of ways this is an accurate-to-the-point-of-distressing metaphor for Bruce's entire life which Tony tries not to dwell on.)
During a quiet flight back from a small conference in Las Vegas—the kind of outing they never seem to have time for anymore, so Bruce demanded they make the time for this one—Tony notices Bruce rolling something small and round between his thumb and index finger. He catches Tony looking, and offers it for inspection: it's a good-sized black pearl of decent color and quality. There are marks on it which suggest it was probably part of a piece of jewelry once.
"She really likes black pearls," he explains. "This was from a pair of earrings I got her on her birthday one year."
Bruce almost never talks about Betty, except sometimes to Pepper or Jane. Tony nods and offers the pearl back. Bruce rolls it in his palm.
"After she found me the last time, she gave me one and kept one. I took it out of the earring so it'd be easier to carry." He starts turning it between his fingers again. "It feels good to hold it. Since she's got the other one."
'Why haven't you asked me to send for her' is a conversation Tony does and simultaneously doesn't want to have. He weighs his options on if now is the time, and decides it's not. He says, "Good luck charm for conferences?"
Bruce smiles. "Yeah, kind of. I take it places I think are going to be...a problem." He pockets it. "Except missions. Don't want to lose it."
Tony spends the rest of the flight back trying to figure out a way for Bruce to safely take the pearl with him everywhere. He ropes Rhodey into the project once he's come up with some ideas, and eventually they produce an alloy that should keep the pearl safe even from the Big Guy. He could wear it maybe as an anklet.
Bruce declines. "It's okay if I can't always have it with me," he says. "It's nice to have something waiting for me here. But, thanks. You guys researching this—it means a lot to me."
Tony makes an anklet setting, just in case. He also has Hill ramp up the security on Bruce's apartment.
At some point he realizes Rhodey has absconded with a pair of his cuff links ("You loaned them to me, we just never worked out for how long."). Meanwhile, Pepper has taken to wearing one of his old, no-longer-functional suit-uplink bracelets. He doesn't actually mind losing possession of either of these things, but he insists for this to all work out there needs to be some manner of trade. Rhodey rolls his eyes and otherwise ignores him. Pepper says she'll think about it.
A month later, by which time he's all but forgotten, he hears someone come out onto the landing pad as he's suiting up for the latest mess. Just before the breastplate snaps into place Pepper says, "Hold on, JARVIS."
"What's up?" he asks, peering around the machinery. Pepper has something in her hand; once she's picked her way through the assembly, she pins two things to his shirt: an old cameo handed down to her from her mom, who received it from her grandmother; and, one of Rhodey's medals.
"For good luck," she says, and pats them both.
He stares down at them for a few seconds and clears his throat. "I thought clothing was the tradition around here."
"No offense, but I'm not letting you wear anything of mine, and Rhodey said you'd just destroy his clothes. So you get pins."
"What about a scarf, like Thor does? You have a ton of scarves."
"Are you saying Rhodey's Air Medal and my grandmother's cameo are not sufficient favors to wear on a mission?"
He opens his mouth, hoping his brain will produce something conciliatory and graceful on the spot, and nothing comes out. Luckily his communicator saves the day by chirping. "Stark, we're ready to go," Barton says.
"On my way," he replies, and switches it to mute. Pepper sighs and smiles at him, then taps his chest. "Try not to get them scratched up."
"Is that the idea? It's good luck because I'm worried I'll ruin it so I'm more careful?"
She bobs her eyebrows. "Whatever works," she says, and gives him a kiss before stepping clear.
He folds an extra part of his shirt over them, and makes a few mental notes on better ways to protect them in the future.