You need washing soda, not baking soda! Very important! It can be found in some Wal-Marts.
Gather your leaves. Waxy leaves work best like Gardenia, Magnolia, Hydrangea, etc. I grabbed Gardenia and maple leaves, straight off the tree/ plant. Place them in a pot large enough to accomodate the amount you want to skeletonize.
Washing soda is a strong base so you may want to wear gloves when handling the leaves.
You will add 3/4 cup of washing soda and 4 cups of water to your pot of leaves. When the water comes to a boil reduce and simmer the suckers. I left mine for an hour and forty five minutes. After 40 minutes it begins to look really ugly..
Keep going, you will need to add more water so your pan doesn’t dry out. I added enough to cover the leaves. The washing soda will crystallize on top.
When 1.75 hours are up fill a glass baking dish with cool water. Gently remove your leaves from the pot. I used a blunt spatula. Place leaves in shallow baking dish with cool water and use a small blunt brush to remove the remaining pulp. I pounced on them gently.
I carefully removed them and rinsed with water and added clean water to the pan. With the spatula I removed the leaves to dry on a paper towel.
If you’re still with me, this is what I ended up with…
I found this at http://www.theidearoom.net/2010/10/how-to-make-leaf-skeletons.html