Dispose of shedding (only after gecko is finished shedding!!).
To clean tank-get everything out of tank-including gecko. Uninstall lighting. Throw away substrate. Spray tank with alcohol,vinegar and water mix, then wipe. Also rinse out food bowls, water and calcium dishes, and wash rocks and caves.
Put in new substrate, put back all materials, reinstall lighting. Lastly, return gecko.
When cleaning tank, put gecko in a spare tank (clean fast, or the gecko might die).