Oiling out is a technique used to even the sheen on a completed oil painting.  When observing your finished oil painting you might see areas that are more glossy than others, or more matte than others.  This is due to differing absorption rates of the oil.  This makes the painting look uneven in terms of its sheen.  The only way to rectify this is by oiling out – varnishing won’t do the trick.

To oil out, take a lint-free cloth and some artist’s painting medium.  Making sure your oil painting is dry to the touch, apply in circular motion until an even finish is achieved.  After your painting dries for at least six months, it is safe to varnish.