> Though, I'm not too clear on why this is a hard problem—couldn't they just, say, throw them into some nitric acid to destroy any organics, like you'd do with

> Though, I'm not too clear on why this is a hard problem—couldn't they just, say, throw them into some nitric acid to destroy any organics, like you'd do with chem-lab glassware? The expensive and tricky part of these (like any) magnetic nanofluid particles is the surface covering that makes them soluble in water but also attracted to oil droplets. Any harsh chemicals would destroy that, and you're left with just fancy rust.