How would I clean my stoma?

Gently. With warm water and a mild soap if necessary. No further cleaning is necessary. I use a soft piece of gauze to do the cleaning when needed.
Gently. Gently cleanse the skin around the stoma when you change the pouch. There are special skin cleansers and also adhesive removers for this use. The mucosa, which is the pink part, does not need to be cleansed; it cleanses itself, and rubbing it will just cause bleeding and irritation. Appliances can be rinsed out at the sink. An enterostomal specialist can help!