Your personal Tumblr journey starts here
Here me out: Bucky Barnes using WD40 on his arm before every stealth mission
Example:
Bucky: *going through his mission bag* gun, extra mags, grenades, DAMMIT WHERE IS THE WD40
Or Tony getting mad that someone stole from his stash, immediately going to Bucky, and turns out Buck has his own stash, and Natasha just stole it for the drama