Fattening or Feeding: This defect, which relates to the paint within the container, is easily recognizable as a thickening of the paint which, in the more advanced stages, renders it unsuitable for use. When thinners are added the viscosity of the paint may even be increased. The cause of this trouble is usually the mixing of certain pigments with an incompatible paint medium. Intermixing paints from different manufacturers should be avoided as this is the most common cause of this defect. Remedy: In most cases the paint must be discarded as useless. If fattening is only very slight it is sometimes possible to restore the paint to normal consistency by the addition of a small quantity of the appropriate thinners. The paint would then need to be used off immediately as the shelf life of the mixed material would be extremely limited.