The study presented in this article demonstrates journalists' abilities to debunk mis-, dis- and malinformation in everyday work situations. It shows how journalists use core skills and competencies to verify the information and it describes why false information evades the journalistic filter and gets published. We combined semi-structured interviews with a think-aloud method in which 20 Estonian journalists were shown constructed episodes of false information and then asked to discuss them. Based on the results, we argue that journalists use traditional fact-checking skills in specific combinations, which is usually sufficient to validate the information. However, when under time pressure, journalists tend to trust their professional experience and take the risk of publishing unchecked information. This risk is even higher when the source seems to be trustworthy and the information is presented on an official social media platform or on the journalist's personal social media page, or if the journalist lacks more indepth knowledge about a specific topic. Video manipulation (e.g. deep fake) and decontextualised photo presentations are the most difficult for journalists to verify, and that is similar regardless of the platform the journalist specialises in. The results of this study are useful for training journalism students and practicing journalists in how to debunk false information.