How would you stiffen an edge for pen clips?

Ive a few little leather pocket pouches ive made that are basically super pretty saddle stiched pieces of oil stuffed sbfoot. Im noticing that the edge on the face where i slip the pen clip on and off isnt looking as crisp. What are my options for spiffing it up?

Do i get it to take up some waxes like beeswax or carnauba, do i get it to absorb some polyurethane or acrylic?

More broadly: is there a good rubric for what to do preventatively for future stuff and reactively for current stuff?

And how should i do it differently for various tanning and oil levels? imgur link here