You can also try asking for some dirty mouse aspen from the pet store.Used aspen straight from their cage, like filled with poop and stinky mouse smells. I've broken my snakes out of hunger strikes by dunking the prey in the bag of dirty aspen and rolling it around in it... essentially coating them with heavy, fresh mouse scent. My snakes take and eat it right away after that.
Also, you can try using the tongs to hold the rat by the scruff of the neck, instead of dangling in the air by the tail. I've found that my snakes are immediately more interested when I hold it by the scruff and have it imitate how a live rat might twitch and move around the cage... instead of strange objects floating in the air. LOL