Fillings that do not scrape the black clean will generally tend to cause secondary caries in the tooth, but if it is in close proximity to the nerve, if you then consider removing all of the black, it may lead to pulp penetration. At this time, the black tissue is hard and there is no way to scrape it off more easily, or you can consider retaining it and then indirectly capping the pulp to protect it as much as possible. If secondary caries occurs and pulp symptoms appear, then do pulp treatment, can retain the activity of the pulp as much as possible, for the benefit of the tooth. So in general the filling should definitely be cleaned of the black, but if it is a special black tooth tissue that is particularly close to the nerve and hard, you can also try to retain it.