I have each of my Russians in their own 3x6' wooden enclosures for the winter, inside my sunporch. Their substrate is coco fiber and organic soil. Every day I pick out their messes, scooping the wet ones when necessary. How often do I need to completely empty the enclosures and refill? Also, can I use a mild bleach water solution after it is empty to sanitize? Or is their a better cleaner?