How would I clean the outside of a huge dictionary from 1935? It’s not leather and on the edges and creases the top layer is flaking off, but would still like to clean it in a way that will not ruin it further if possible.

The book has been handled quite often in the past month and some spots are coming back to life just from people’s hand oils, but it’s still mostly dry and dirty. It’s not extremely valuable. I don’t see any mildew. I’m thinking to moisten a clean rag in some warm water with a drop of soap? or would it be better to use a ph-neutral leather cleaner? I’m open to suggestions. I’m not sure if a link for photos would work here [https://imgur.com/a/KmPdnVh](https://imgur.com/a/KmPdnVh) TIA!

by futureconstruct