I love Brandon Sanderson. I really do. But a scene in Warbreaker where one of the characters sheathes a bloody sword seriously made me twitch. All though I may give him the benefit of the doubt, because it was a bad guy who did it. Maybe Sanderson did it on purpose, because only a really bad guy would treat their sword like that....
Or maybe I'm the only one who noticed.
I have scene the same sort of thing from other books as well (but of course none of those books were as awesome as Sanderson's). The victorious hero will be standing above the bad guy's slain minions, bloody sword in hand. The battle is over so the hero takes his bloody sword and sheathes it. Now, before I start screaming and ranting, lets think about this. You have a sword that is covered in blood. A piece of metal covered in a liquid. Moisture is the enemy of metal. Dirt and debris on the blade will scratch it. Getting a scratch on your blade in the middle of battle is one thing, marking up your blade because you're too lazy to take proper care of it is another. Something as small as the oil from a finger print can leave rust marks.
If you want to take good and proper care of your sword (The sword that, by the way, your life will depend on in the middle of a battle) clean it off! My sword master wipes down his blades with 3 in 1, but the first step is to get all the blood and dirt off.
Keep my eye from twitching, have your characters clean their blades!