If you're running a local model, in most cases, jailbreaking it is as easy as prefilling the response with something like, "Sure, I'm happy to answer your question!" and then having the model complete the rest. Most local LLM UIs have this option.
A lot of the models in Ollama you can already easily bypass safe guards without having to retrain. OpenAI's open source models can be bypassed just by disabling thinking.