Cleaning
Tank
Once a month the tank and its decor needs to be thoroughly cleaned out with detergent and boiling water. Removing snail slime can be a little tricky but persistence pays off. Apparently, vinegar can get really tough stains off.
You MUST rinse the tank extremely thoroughly. This cannot be stressed enough. Failure to completely rid the tank of any cleaning agents or chemicals, will result in the snails being poisoned. In a situation where the tank is too heavy to be cleaned aggressively or rinsed thoroughly (eg. large glass tanks) boiling water will help to sterilise it rather than using detergent.
Snails
You should bathe your snails regularly to help keep them clean and free from pests. NEVER completely submerge the snail because they will drown. It is better to sit it in a shallow dish of room-temperature water and then run the water over the snail's body. Make sure the water is not too cold or too hot. Room temperature is ideal.
To clean the shell use either your finger or an old, soft toothbrush to gently brush away any dirt etc. off the shell. Heavy scrubbing is unnecessary and may scar the shell so never scrub too hard or use a hard-bristled brush. It is also helpful to use a plant sprayer. NEVER use detergent or any cleaning fluids on the snail.
You can polish the shell by gently rubbing sesame seed oil on the shell using a piece of non-rough cloth or lint.
Substrate
In each case, make sure the water is clean, don't add any detergent or cleaning fluids because they will be soaked up by the substrate.
Peat
Some types of peat are quite large grained and you may find that it can be rinsed using a sieve or colander. It can be sterilised in the oven by baking it at 200°C for 1-2 hours. It must be noted that dry peat is absorbent and needs to be moistened before the snails are returned to it. Also, it stores heat very well so make sure it is cool all the way through before putting it back in your tank.
Potting Soil
Potting soil is hard to clean with water because the particles are so small. However, it may be possible to put it in a sieve with small holes and flooded and then squeezed dry. However, the effectiveness of this is questionable. It can be sterilised in the oven by baking it at 200°C for 1-2 hours. It must be noted that dry soil is absorbent and needs to be moistened before the snails are returned to it. Also, it stores heat very well so make sure it is cool all the way through before putting it back in your tank.
Coir
Coir can be sterilised in the oven by baking it at 200°C for 1-2 hours. Dry coir is absorbent and needs to be moistened before the snails are returned to it. Also, it stores heat very well so make sure it is cool all the way through before putting it back in your tank.
I have no experience of how you may clean coir with water but I imagine it is similar to potting soil.
Vermiculite
Vermiculite can be cleaned by putting it in a sieve and vigorously running water through rather like you would with rice. It can be sterilised in the oven by baking it at 200°C for 1-2 hours. It must be noted that dry vermiculite is very absorbent and stores heat well so it need to be soaked in water and fully cooled before the snails are returned to it.
Bark
Bark can be cleaned by putting it in a colander and vigorously running water through it rather like you would with rice. It can also be rinsed in a bath/shower because most of the pieces will be too big to go down the plug-hole.
It can be sterilised in the oven by baking it at 200°C for 1-2 hours. It must be noted that dry bark is absorbent and needs to be moistened before the snails are returned to it. Bark is prone to mold and fungus so it is recommended you have two batches that you alternate to give the bark a chance to dry out and breathe.
Sphagnum Moss
Sphagnum moss can be cleaned by putting it in a sieve or colander and vigorously running water through it. Sphagnum moss is supplied alive so don't attempt to dry it out or sterilise it with boiling water.