Prompted by discussion in comments of a recent question whether PLA is suitable for parts that need to be in contact with acetone, I did some casual experiments and found that my clear/"natural" 3D Solutech PLA is mostly but not entirely resistant to acetone, while my blue Hatchbox PLA is quickly softened and deformed by it. This got me wondering: how do you go about finding PLA that's actually PLA (and nothing else)? Just "clear/natural" in product description does not seem to suffice.
I know this is close to a shopping question, so please make suggestions on how it could be improved if it's too close. It'd be great if there were keywords that worked, but an answer is probably going to be more along the lines of how to go about inquiring with manufacturers or where to find places where manufacturers might advertise that their products as pure.