Posted: 13/10/2014 at 18:59
Fishy, you can re-use it providing you replace all of the nutrients (including micro-nutrients aka trace elements.) After all, commercial compost made from coir and the like has no nutrients in at all it until they add them during the manufacturing process.
Having said that, you do risk pests and diseases building-up. Personally, I put all of my used compost on the borders and other areas as my clay soil needs every bit of organic matter it can get.