I save up used grease whenever I have some left from cooking. Bacon drippings, shortening, whatever you have left over. You can save a bunch and make a big batch or save a bit and make small batches as you need it.
It's a great way to use up left over bits of stale stuff, too!
Take your grease and melt it in a BIG pot.
No, not that one, the bigger one. Trust me on this.
I forgot a picture of this, but I put a big spoonful of crunchy peanut butter in there and melt it in. Then you add in any stale or left over bits of breads, cereals, crackers, etc. I actually have a big ziploc bag in my freezer and anything that's getting stale or left over and I know won't be eaten (but would be good for suet) goes in there until I'm ready to make a batch.
This time I had one lone piece of cornbread to add.
Some popcorn the kids got from the local hardware store but didn't eat before it went stale....
Throw in some birdseed....
A bit of cornmeal (or flour) for thickening....
Add some oats just because I know the birds like it and it helps thicken it....
Some stale cereal a friend saved for me.....
(Yes, it IS acceptable to ask your friends to save stale food for you!)
I also threw in a big handful of our sunflower seeds and a handful of raisins.
You want to add things until it gets really thick and hard to stir.
If you've bought suet you can save those plastic things and put your suet in there so it will automatically be the correct size. I just pulled a few boxes out of the recycling pile and lined them with foil and spread it out in there. Then I popped them in the freezer to harden up all the way then score them to cut them to the size I want. I keep mine in the freezer here but if you have a place in your house that stays cool, you can keep them there.
Trust me when I say your feathered friends will be VERY happy with your concoction, no matter what you throw in there!