So as the title. I have left some positive trust ratings to proven scammers, before they started to scamming people. I then left neutral trust ratings once I found them starting to scam people.
Should I delete both the positive and neutral rating and change it to a neutral/negative one, or just let them be? Please give some advice.
If someone has started scamming people, I would remove the positive trust right away, as it reflects poorly on you.
Neutral trust is different, it doesn't really affect their score.