You may want to OP minimum 2 times daily to work on your stains. Some have OP 3 or more times. It's perfectly safe; we're using a food and not even swallowing it. As you can read in his posts, Trapper/kcmo OP's several times during the day.
I know what you mean about your teeth feeling so clean after brushing with bar soap. I'm using Kiss My Face pure olive oil soap. Its flavor is not strong, and as Dr. Judd says, 2 rinses and it's gone.