Water and soap (only) is probably a bit less that I'd suggest for this problem.
Get the bulk moldy glop out and wash with water and soap, then rinse.
Fill with Water and chlorine bleach, and a nice long soak (overnight, or even a few days) would be one further component of a through cleaning.
Rinsing very well (do not combine disparate cleaning chemicals) and then using baking soda (sodium bicarbonate) with adequate boiling water to fill the pot would be another step - let that soak overnight as well.
Rinse throughly, wash again with water and soap, rinse throughly again, and give it the "sniff test" - if it doesn't smell moldy, and it looks clean, you are good to go.