If you have plain charcoal briquets…NOT the kind with lighter fluid!..put the yarn and charcoal together just don’t get the charcoal on the fibers. I have charcoal in my sweater drawers and closet to neutralize odors. I break the briquets up into pieces small enough to fit into an empty plastic spice bottles (like you get at the dollar store) with the ‘sprinkle’ tops on so the air can get in but the charcoal can’t get out. The charcoal has no smell and doesn’t impart any into the fabric. You can also buy charcoal in bags for odor (at home improvement stores, etc).
I’ve worked with acrylic for decades, and have chemical sensitivities, but have never encountered a problem with it.