A residue of sunflower oil in the bottle that has already gone bad can be disposed of with the bottle as a whole. However, the bottle should be tightly closed so that no oil leaks out.
The bottle can also be wrapped with paper or kitchen roll to prevent a greasy film from forming in the waste bin.
Small amounts of sunflower oil can be disposed of down the drain. However, too much oil in the drain will lead to blockages in the sewage pipe.