Yeah, the easiest way to fix that is to consume another soul just as pure as his is. They cancel each other out.

I tried the opposite and that didn't work in case you were gonna suggest that.

[ it was gross! so bitter and he makes a face at it because ick!! ]

The only other way is to convince him to leave and I've already tried that.

[ keyword: he's tried that, not anyone else. it's something minami won't explicitly say though because he really doesn't like the idea because it's dangerous. ]