Papermaking
Pull out the plants, boil them, beat (or blend) them, and turn them into paper.
Krater Collective and Trajna run a commerical project producing paper out of knotweed and recycled paper. You can learn more about it here.
Meg Heeres hosts the Invasive Paper Project hosting workshops and making art out of plants like phragmites, amur honeysuckle and russian olive.
Joshua Ralph has also hosted workshops using various invasive plants along with recycled paper.