As a skinner, I am unable to use Bloods of Sargeras. Over the course of the expansion, I have piled up 817 Bloods from skinning. I reserached that Fjarkskaggl is the most profitable resource on my server at 49g a piece, which means if I buy 10 Fjarnskaggl for 1 blood, I get 490g per blood. It is a quick way to put money in your pockets before the prices on these reagents drop. Half of my 400k gold worth of Fjarnskaggl has sold in less than three hours.
http://puu.sh/rVDA8.png
Look up what is the most profitable reagent on your server and invest your bloods in them.
You can exchange bloods in at Illnea Bloodhorn. (Located to the right of the herbalism building in New Dalaran)
Hope you guys find this useful.