Aluminum Acetate is used in mordanting mainly cellulose fibers that are a little tricker to grab natural color. Often paired also with a tannin base to grab the color even better. you will need an afterbath dip in chalk or bran. This process is called "dunging."
Use a total weight of 8% to WOF
Full explanation of mordant process on our blog or in the Natural Dyes virtual class!