I use ollama every day for spam filtering: gemma3:27b works great, but I use gpt-oss:20b on a daily basis because it's so much faster and comparable in performance.
It's amazingly accurate.
The interesting thing is that after experimentation I found that it's best if the prompt doesn't describe what is spam. The LLMs are somewhat "intelligent", so the prompt now describes me — who I am, what I do, my interests, etc. It's much more effective and generalizes better to fight new kinds of spam.
And a nice side observation is that this kind of system requires no training (so I no longer collect samples of spam) and can't be gamed, because it describes me instead of describing specific kinds of spam.
I have to write it up in a blog post.