Flaws in fining can result from incorrect or wrong fining agents or incorrect application. Substances with high adsorption power such as activated carbon or bentonite can very easily take on tones from their surroundings. Therefore, they must not be stored in musty rooms or next to strong smelling substances such as petrol, diesel oil, dyes or petroleum. But even a plastic bag, for example, can already transfer negative tones into the wine. Protein-containing or protein-containing agents such as gelatine, house blister or casein can spoil relatively easily. The most common mistake is the bitter almond tone due to a faulty blue hue (overshading). See also under vinification and wine faults.