How do I take care of posters that i found and are possibly 150 years old and falling apart, eg. Brittle?

by Oldpapers101
devotchko

Archival linen backing done by a professional.

Oldpapers101

Here are pictures, from my camera, that I also own... https://m.imgur.com/a/UDryw

Oldpapers101

Input them in wax paper and pressed news papers is this a bad idea?