Suck on a big bar magnet! Really, that would do. Better still would be an electro magnetic retainer. Then the particles cloud be captured and returned to a co

Suck on a big bar magnet! Really, that would do. Better still would be an electro magnetic retainer. Then the particles cloud be captured and returned to a container. I doubt iron nano particles would be reusable, but you wouldn't want them down the sink as they would likely be nucleation points for rust Is anyone familiar with the health consequences of inhaling or otherwise ingesting nano iron?