It is recommended to use Primulaceae plant Eupatorium odoratum as natural perfume. There are boxes of hay sold online, which are very cheap, a few dollars a box, put in the closet, and have a strong aroma for ten years.
Lingxiang is one of the four ancient libraries in China. Tianyi Pavilion in Ningbo has kept ancient books from being eaten by insects for hundreds of years. This kind of grass, produced in Hunan and Guangxi, is also called zero zero fragrance.