Sometimes a solution of hot water and baking soda helps. But you need 2 tablespoons of baking soda and 1 tablespoon of warm water. This way, you make a paste of water and baking soda to make the cleaning effective. With this paste, using a sponge cut in half or an old toothbrush is very convenient. But I haven't cleaned with vinegar or baking soda for a long time because I've recently contacted a high-pressure cleaning company. I like the result of such cleaning better because the specialists from the cleaning company use just clean cold water. Water always cleanses even the greasiest and dirtiest stains on metal or plastic surfaces. I cleaned my dirty roof like that.