Here is a perfectly ordinary red district in Anitam. Nelen parks his truck at the recharge station, and the next driver takes the handoff, and Nelen stretches out the kinks in his back and heads home.
"Not even if I could prove to them that the alchemical procedure to remove the property was effective?"
"Well, fair enough. And I don't even know if I can do it, I'd have to find out if the property is alchemically detectable or not first. Quite a lot of properties are, though."
"I'd need alchemical tools—the same kind of glassware that works for chemistry is usually fine in a pinch—and some samples of things with and without the property, ideally things that are otherwise very similar to each other. The classic example in introductory alchemy is to leave out two trays of sand under the sky for a week, covering both to begin with and then uncovering one during the day and the other at night, and then alchemically process them to reveal the day-nature and night-nature respectively. Finding 'polluted'-nature will be harder because it's never been done before, but the basic idea is the same. I could do it very slowly using only natural alchemy, or much faster using infernal magic if you didn't mind the tools and samples ending up slightly infernal."
"Not in my opinion. It would be inconvenient for you if you ever had to bring those specific objects to Earth, but it seems very unlikely that you'll ever have the occasion to do that."
"Hmm. I'd like to verify the principle before I leave... I've done alchemy in a mundane kitchen before, in a real pinch, but given the nature of the property under investigation I don't really want to inflict it on anyone's kitchen... even if you all already have it, I imagine you still don't want some of those materials interacting with the tools you use to prepare food...?"
"I thought as much. Well—I'll leave it up to you, I think. If someone wants to lend their kitchen to the cause of finding out whether 'polluted'-nature can be alchemically isolated, I'm more than happy to try. I'll clean everything afterward as best I can, of course."
"Thank you, I appreciate it."
"I'm not sure. Depending on how difficult it is to fix my leg, I might be walking unassisted within the week, or not for several."
"Logical, since I'm an alien. I don't know what effect your medications would have on me."
"I think I'd rather wait. Being able to stand up without it will probably also make the procedures for leaving easier to follow."
"That would be appreciated but I've managed all right with worse; I won't be upset if no one else volunteers for an alien houseguest."
"I think I am all right for the moment. Is there anything else you want to ask of me?"