Hello, MMOwned. I have lurked for a while but now I think it's about time I contribute something.
I discovered a bug where you could preserve any materials used when crafting something. I am still working on a way to reliably reproduce it, but here it goes:
1) Begin crafting.
2) Open your bags, move the materials around to different slots quickly.
It's that simple! It works sometimes, no it's not a visual bug, I really could save one or two items for my next craft. I suggest you practice with Frostweave bandages. Hopefully someone down the line will make some sort of auto bag shuffler to aid with this.
I hope it works for everyone else, and enjoy.