Predatory journals often prey on innocent researchers who are unaware of the threat they pose. This paper discusses what researchers can do if they unintentionally publish a paper in a predatory journal, including measures to take before submission, during peer review, and after the journal has accepted a manuscript. The specific recommendations discussed are pre-registration, pre-submission peer-review, open peer-review, topping up reviewers, post-publication peer review, open recommendation, and treatment as unrefereed. These measures may help to ensure the credibility of the article, even if it is published in a predatory journal. The present article suggests that an open and multi-layered assessment of research content enhances the credibility of all research articles, even those published in non-predatory journals. If applied consistently by researchers in various fields, the suggested measures may enhance reproducibility and promote the advancement of science.