The kind that's sold in a circular tin is much easier to work with than the sticks. A DDG image search should show plenty of examples.

I've always put mine into Mason jars. Do this with bacon grease as well. Once I get enough I slowly bring the jar to a warm enough temp to liquefy the tallow (using standard jarring techniques) I place a lid on with gloves and let all the impurities settle to the bottom. This makes the majority nice and clean plus seals the jar nicely for extended shelf life. This let's me have multiple smaller amounts that keep for long periods of time.

Bit late to the thread, but I just season my pans with the same oil I use for cooking. (Olive oil this last time, in fact, just because it was in a squeeze bottle and I couldn't be bothered to pour out of my large jug of canola.) It's fine.