I use Wipe Out 1 terrarium cleaner/disinfectant. You can find it at most Petsmarts. I remove all items and old soil. Wash the remaining soil off the walls of the inclosure with de-chlorinated water then dump that water out of the tank. I then dry the tank by wiping down with paper towels. Then I spray the tank down with the Wipe Out 1. It has to sit for 5 minutes or more then you just as the name says wipe it out til dry and no more of the disinfectant is in the tank. As a precaution since amphibians are so sensitive to chemicals I wash down the tank again with de-chlorinated water and wipe dry again.
You can't use Wipe Out 1 on water dishes and tank items like fake plants. You have to use Wipe Out 2 which I can never seem to find so I buy Jurassi-Wipes which are also used to wipe down stains and strong odor spots in the tank. Since my tanks never smell horrible or bad at all I just use them to wipe down my water dishes and fake plants. The wipes contain lime and citrus oils to attack smells and staines. You must let your tank and terrarium furniture air out before returning them to the tank.
Underneath the coco fiber on the bottome of the tank I use the Zilla Terrarium Liner. This liner is made like outdoor carpet so water and moisture pass throuh it easily. Its only purpose is the act as a small drainage layer and to keep my frogs off the glass where their urine will settle with the excess water. This way the frogs don't absorb any of the urine/amonia. You can wash these liners but I recomend disposing of them after 2 tank changes. Mainly because you can't use harsh cleaners on the carpet for fear of them staying in it and possibly killing the frog. I soak them in scalding de-chlorinated water to kill germs and remove urine and amonia. I also rinse them in scalding de-chlorinated water.
As for humidity I have my screen tops covered with plastic wrap on 3/4 of the lid to hold in heat and humidity. Unlike most her though my humidity and light setup is almost automated. My frogs 12 hour day night cycle is controlled by a Zilla Power center which is a large serge protector with a tmer built in that turns my frogs light on and off at the set times I've saved into it. The humidity is controled by a Zoo Med Hygrotherm temp and humidity control unit. It has a sensor that you place in the desired area of the tank and set the temp and humidity levels where you want them and save them in the unit. If it gets too hot the unit will turn off heat units for your inclosure or turn on cooling units like fans to cool the enclosure down. If the humidity drops below your settings it will automatically turn on a fogger(humidifier) or misting unit to raise the humidity back to optimal levels.
I have 2 Zoo Med Repti-Foggers hooked up to the Hygrotherm to keep humidity up and they turn on to raise the levels in the tank when it drops. Now these Hygrotherm unites have some tolerance levels. It won't kick on everytime the humidity drops 1 or 3% below set level of humidity. You can set the amount of % points it can drop before kicking the foggers on so its still in the correct range and not running everytime it drops to 79% which is good because it keeps the humidity within the correct 70% to 80% range all day.
You still have to mist the soil so it stays moist. The fogger units to help with the moisture levels slightly due to them keeping the humidity up and some of the water vapor condensing on the substrate. You must use Distilled water with fog machines(humidifiers) otherwise mineral and calcium deposites form on the condenser of the unit and cause its life to drastically be short.
Please note that distilled water is only for misting and foggers. You can't use it for your frogs water because the distilled water is the cleanest form of water and contains no minerals or salts and will actually steal your frogs vitamines and minerals from them if they were to soak in it. Thus killing your frog over time.