"Cando" has an awesome post, with pictures for a great recipe.
http://www.finchforum.com/viewtopic.php?f=3&t=11830
But, I am wondering specifically about finches.
Really good article here: http://www.efinch.com/grit/grit.htm
Egg shells and cuttle bone are always available for my guys here. I also use "F-Vite" powder in the egg food mix.
"F-Vite is a combination grit, protein, energy, vitamin and mineral supplement, which is especially beneficial for breeding and young molting birds, but is used all year round."
I have run out of the blue Higgins grit. Wondering if I need to get some more, or if it's unnecessary.
What do you all do?
Sorry if this is a redundant subject, I did a search, but didn't find a topic specific for finches.

Lauren