If I was to reuse coco coir I would soak it and then flush it well and blend in with some new and some new perlite......... I will definitely reuse coco chips.
yes coco could be reused as long as it is cleaned well. but it breaks down to fine partices with time so you will need to add airy stuff to it to prevent over watering. perlite and coco chips as mentioned above are a good option