How To Flatten Old Bills? Need More Than A Book. Eye Appeal Is My Priority.

If they were mine I'd try a "do-it-yourself" approach before sending stuff off for "conservation".

Here's what I'd try:

Find and pull a couple of comparably worn current notes from circulation to work and experiment with BEFORE trying anything with your damaged old notes.

Take one of the notes you pulled from circulation and place it flat on a plate of warm water for a few hours. Do not rub the note or try to flatten any folds or creases. Next place the wet note between two white cotton hand towels to start the drying process. Next take a steam iron and using low heat, gently iron the towels that are holding the wet note. After a few passes of the iron take a look at your note and see if it looks better. The heat will help evaporate the water remaining on the note and hopefully mitigate the wrinkles and creases. It may take a few minutes but continuous ironing will slowly evaporate the water and hopefully improve the appearance of the notes you are experimenting with. Take your time, avoid high heat, any kind of cleaning solution or starch and any direct contact of the iron with the note.

Hopefully, you can get an idea of what you can accomplish on your own. If you decide to work on your damaged notes start with the less valuable ones first and go from there. If you are uncomfortable with your results on your experimental notes then send off the GF damaged notes for professional conservation as Steve suggested.

At least the ex didn't take a pair of scissors or a magic marker to them! I've heard horror stories the past 50 years!

Good luck!

I've tried something similar to @westernsky's process and it has worked well for me.

Looks like a solid plan. Certainly test the procedure on some spendable notes first.

I'm happy to report, I seemed to have flattened all the bills quite effectively & without causing further damage! See the image at the bottom of this post.

I used an iron on low heat with filtered water steam. I was too afraid to actually soak the bills, but I'm not sure it could've turned out much better. Maybe soaking them would get some of the super-deep wrinkles out, but I was afraid it would come at the cost of rips due to fibers being too relaxed.

The (possibly overly-descriptive) instructions for what I did:

- Place a cotton hand towel on top of the ironing board.
- Place a bill on the cotton towel. Make sure all folds are facing the correct direction / aligned.
- Spray both sides of the bill pretty heavily with steam from about a 1" distance (hovering), until the bill feels damp to the touch on both sides.
- Place another cotton towel on top of the damp bill and iron through that top cotton towel.
- Try to make sure the cotton towels didn't move during the ironing process.
- Iron with firm pressure and move the iron very minimally in a tight circular motion. Try to mentally picture where the bill has wrinkles / folds and push those wrinkles / folds outwards towards the nearest edge.. Like normal ironing.
- Have the iron on the dry setting, but for deeply wrinkled bills spray steam as-needed during this step of the ironing.
- Flip the bill halfway, replace the top towel and repeat to the other side.
- Once 90% of the water is out of the bill, remove the top towel and place the iron directly on the bill with light - medium pressure.
- Don't spray any steam when ironing the bill directly, make sure your iron is on the dry setting. The goal is to dry out the bill flat, without it curling in either direction.
- Flip the bill, do this to the other side but just where the bill is curling. Do this until the bill is no longer curling in either direction / in a flat equilibrium state.
- Have a book ready, quickly place the bill in between book pages and sit / stand on the book for 15-20 seconds while the bill finishes the drying and cooling process.

Thanks for your input westernsky & SteveInTampa. :-)

They certainly look better than they did! Good outcome for sure!

The sun, moon and earth sure lined up for you today!

Terrific results. Thanks for sharing

Yes, and yes.
I believe the OP's main concern was eye appeal and not original paper quality.