For flaxseed oil to be at its optimal best, it must be cold pressed from the linseeds, & instantly stored in the dark to retain its properties. It should be kept in a fridge in a light proof container. If it is grown organically it is ideal, but difficult to get,& more expensive. The most inportant thing is that if it smells of just a hint of oil paint,it is already turning rancid, & should not be consumed. Those of us who have delved in oil painting are well aware of that odour,& so I now paint in acrylics instead.