Question

Veins carry stale blood there is one exception which veins are the exception

Answer 1

I believe, the exception to stale blood veins are the pulmonary veins. These veins carry oxygenated blood from the lungs to the heart. They carry blood that is rich in oxygen to the heart, which is then pumped to all parts of the body through the aorta. All the other veins carry blood back to the heart after oxygen has been delivered to the various body parts. 

Answer 2

The pulmonary veins are the exceptions.  

The pulmonary veins are the veins that are part of pulmonary circulation and those veins transfer oxygenated blood from the lungs to the heart.  Two veins, one from each lung transport the blood to the left atrium of the heart.