mounting old documents

[flathead]

A customer has brought me some documents they would like framed. (title deeds etc to the house they have bought) some are over 200yrs old.
They were folded and kept in a box in the house by all the previous owners.
The paper is quite thick and the folds / creases are not going to give up easily.
Some of the papers also appear to have a waxed surface.
I dont want them to go completely flat as it would ruin the patina.
any suggestions?
thought about trying to iron between two sheets of brown paper but wondered if any of you had come up with better solutions.

[JFeig]

"WARNING, WILL ROBINSON' Those thick waxy sheets might be made from parchment (animal skin: sheep or goat). They will not survive excessive heat.

Contact a specialist(conservator) for advise .

[flathead]

thank you for that, warning heeded

[pramsay13]

I had an old blueprint document in for framing and we had the same discussion about not wanting to stick it down as the bumps and folds formed part of the document's history.
In the end I just flattened it under some mountboard for a few days and then hinged as normal. It is reasonably flat but not completely stuck down.