The following is quoted from Muji website:
"This soft non-woven fabric, made using traditional Japanese papermaking techniques, effectively wipes away dirt from glasses, smartphone screens, and other surfaces.
[Notice of Material Change] Due to the discontinuation of the acrylic nonwoven fabric previously used, we have changed the material of the nonwoven fabric. The new eyeglass cleaning cloth is made of nylon and PET nonwoven fabric, which is soft and tear-resistant."