Does anyone have best practices for a new mod that wants to clean up a "messy" leaderboard? Some of the runs have obvious wrong times, which is easy to justify removing. But there some individual mission leaderboards where every run is players failing. However, there are no rules listed, so it's not 100% clear the intent of the category. I'd like to update it so that only true passing missions are counted, that way they can tracked, but I'm not sure if it would be wrong to remove old runs because they no longer meet the intent of the category. Some mission types do have fail leaderboards as a category, but others do not.

If it makes a difference, almost every mission can be failed in 1 second by not doing anything at the start. So as a category I think it's pretty stupid to begin with. At least 80% of the runs on this game are just people getting the 1 second fail so they can say they're tied for first on the leaderboard. For additional context, when I started running this game two months ago the latest run was 8 months old, so maybe none of this even matters because I'm the only one running it. But I'm also fairly new to participating in speed running (just watched a lot), so I don't know what's normal.

Any advice from other mods or long time speed runners? How does one correctly go about adding category rules and cleaning out bad runs? Should I just leave it as is and personally track my own runs with the rules I think actually fit the category intent?

I personally think you should just make a separate category for the runs that just fail the missions, so you don't have to remove any runs.