Due to its smell, bleach serves as a terrific rat repellent. But it can act as an effective poison too. That’s because rats can’t ingest it and live. But the smell is likely to keep them from getting too close so if you want rats to ingest it, mix a little bleach with a tablespoon of peanut butter. You may have to add more PB to disguise the odor. Set the bait at a mousehole or other entry point.