If you are trying to poison rats, you occasionally see that they refuse to eat the bait, regardless of the type (block, grain like Decon)etc. We found a way to get them to take the bait is to pour some hot fresh bacon grease over it and set it out. Not only will they eat the poison bait, they'll eat the package you have it in. We used this technique on the farm for years. A day or two later, you'll find the dead rat outside. To speed the action put out a separate shallow bowl of water close.