A Reader Question: How do you navigate chemical finishes on garments?

A reader question:  

Dear Ms. Aldrich,

I have been infatuated with your blog for years and check almost daily for updates or scour the archives. I have now started to read everything going back to the beginning, a real treat. Thank you for this vault of knowledge.

I have a wide collection of clothing consisting of natural materials as often discussed, of which the staples are of course cotton and wool. In Europe, the material composition is mandatory to name on the label of the garment. Yet, what I have learned only recently, there is a wild variety of icky finishes possible (the more obvious ones being non stain, non odor, wrinkle free nonsense etc.) but apparently also heavy toxins, formaldehyde, etc. I was baffled to learn it is not mandatory to explain what sort of paint was used to colour the garment, what finishes have been used on the garment (even when it is cotton, certified organic, OEKO-TEX, etc) and which chemicals have been used in production. I have just never considered the wide variety of possibilities here. Is this something you have learned to navigate or perhaps your readers can offer more insights? Naturally, when I ask clerks “what can you tell me about the finishes on this garment” I receive the most impressive sheepish looks with a mumbling of “no one asks that ever or cares about that, you old git”. 

I’d consider it my next step in really, totally going overboard with the wardrobe in having only the purest forms of clothing possible.

All the best,