I hope your talking about going from live to frozen mice/rats. Luckily when i switched over my ball never missed a beat but I know some have problems converting. My suggestion is first to have a pair of large feeding tongs. I will first put the frozen rat in a sandwhich bag so it doesn't stink up the place. Then I heat up a cup of water so its warm but not boiling and place said bag in the water.I wait awhile, oh thirty minutes or so and check to see if its completely thawed out. Once thats done simply grab the food by the tail with the tongs and position it slightly in front of your ball and a little above the ground. A little bit of wiggling or moving should hopefully help trigger the feed response.
I'm not exactly sure what is meant by "death food" either, but if you're talking frozen thawed, I second bander's suggestions. I always defrost mine inside a plastic baggie in hot water, and one thawed and warmed I just dangle them by the tail with some feeding tongs. No problems from either snake (when they are hungry of course), but mine were raised on f/t from hatch so I had a leg up.