Recognize retained background islands and distinguish them from real subject details before choosing a repair.
Look for attached and isolated patches
The model may include a region of the old background when it resembles or touches the subject. Common examples include a chair behind a person, a tabletop beside a product or a patch inside a handle. These can form a smooth but incorrect extension of the cutout, so edge smoothness alone is not a reliable quality check.
Compare color and structure
Switch to a contrasting background and inspect the suspicious area. Compare it directly with the original. Ask whether it belongs to the object, is empty space, or is another object that the model grouped into the foreground. Do not remove a real white label simply because it resembles the original white wall.
For a handbag, the handle itself should remain while the empty space inside it should reveal the new background. Both may be light in the source, but their structural roles differ.
Choose a source change or manual edit
ToolNivo does not currently provide an erase or restore brush. A better source with more separation can reduce the problem; a tighter crop can help when it removes competing objects without cutting the subject. Otherwise, refine the mask in a dedicated editor. Avoid hiding the retained patch under a matching background if the asset needs to work on multiple colors. Keep a transparent master only after confirming that its interior gaps and outer boundaries are acceptable.