The phrase "putting a lid on" typically means to contain, control or put a stop to something. Antonyms for this phrase could include "unleashing," "unbridling," "freeing," "allowing," "encouraging," and "permitting." Instead of putting a lid on a situation or keeping it under wraps, one could choose to openly discuss or address it. This could involve "confronting" the issue, "exposing" it, "revealing" the truth, or "unveiling" the details. These antonyms suggest a more open and transparent approach to handling a situation, as opposed to shutting it down and keeping it secret.