Toughen up chicken livers for catfish bait by packing them in a coffee can between layers of non-iodized salt. Store the can in the refrigerator for about a week, and the livers will toughen up to the consistency of leather.
If you want to know which baits work best for catching giant flatheads and monster blue catfish you need to read this page. There are pics of the baits too. If you don't get a bite you can't catch the monster catfish!