https://wccftech.com/apple-19-polishing-cloth-teardown-by-ifixit/

It appears that whatever Apple releases, it ends up selling, even if it is the $19 Polishing Cloth. The cleaning accessory is now backordered, with the company’s website saying that you will not get it for 10-12 weeks. One could conclude that it is a high-quality item, which is why it sold out so rapidly. However, its popularity was likely due to Apple’s brand name than anything else, as there was no in-depth look at the materials at the time, until now. iFixit provides a closer at why you have to pay a premium for it, even if it is just another cleaning cloth.

Unlike iFixit’s more intricate disassembly processes of various Apple products, the $19 Polishing Cloth has no circuits hidden under its fabric. What is different about it is that it is two pieces of cloth glued together. Whether or not that helps with the cleaning process, iFixit did not specify.