Effectively you could take a watch glass or a petri dish, either not compress to a pellet in the first place, or just break up your sample gently between your fingers into the onto the watch glass or into the Petri dish, then just place that on top of the biggest magnet you can find and pluck away any floating fragments with plastic tweezers… seems simple… assuming you appreciate the sorts of thing’s about solid powder chemistry (which can seem a lot more like applied geology than the kind of chemistry most people are used to)…

if you want to see some interesting things and like a good chemistry video I thoroughly recommend searching for dry powder on powder chemical reactions… most of them are fire related demonstrations but it can be interesting to see them gently spoon a powder on top on another powder and nothing happens, until they poke it with a stirring rod hard enough to press the powder firmly against the other powder and get the reaction surface area to increase and then it’s off to the races… physical contacts between materials can sometimes not be in as much contact as you think… even when it’s literally pilled on top of the other stuff.