FWIW: These sorts of spade connectors are quite commonplace --- you can find replacements on all of the usual electronic component retail websites, with a per-part price of around a few cents. What I would do is remove the old connector and replace it with a new one. If clipping off the connector would make the ground lead too short, I'd extend the lead with another length of wire and attach the replacement connector to that. I think this would be a more dependable and effective solution than trying to repair the connector you've got.
This particular connector does not carry a lot of current and wouldn't tend to get hot.
