Not if you don't spray it. To keep EcoEarth moist you have to soak it right off and then keep spraying it. It actually dries out rather quickly, especially when you add the lighting/heat that the skink requires.
If you use the brick things, just soak it to 'open' it and then spread it out on a plastic sheet or something to dry out. Once it's nice and dry you can put it in the enclosure. Any earthy substrate should work well, as long as it's not packed wet. A little moisture won't hurt, so spilled water isn't horrible.
Sorry if that sounds disjointed... I'm really tired.