Take your time rehydrating it, water it to runoff several times over a 15 min period. Once a pot gets very dry, it doesn't matter if you're using peat based or coco, it's very hard to get it rehydrated again. You can pour water through it and the pot stays almost just as light as before. Taking your time to rehydrate it, plus the yucca or soap, will help fix this. You'll know it's rehydrated by the weight of the pot. Try not to ever let them get bone dry, or you'll have to fuss with rehydrating them constantly.