How to make rust ink

I am so excited about the new book The Organic Artist: Make Your Own Paint, Paper, Pigments, Prints and More from Nature by Nick Neddo. This technique for making your own ink with rusty objects and vinegar sounds just like the kind of project I want to try and would be perfect for fall crafting as the color reminds me of fall leaves. I bet it will look great with mixed-media projects that call for an aged natural look too.

Love using natural materials found in nature? Check out these books on Crafting with nature.