Sayyed Sistani says:
"Washing the teeth does not invalidate the fast as long as the person does not swallow the saliva that has mixed with the mouthwash or toothpaste. However, the lingering flavour or taste of the paste that mixes with the saliva does not affect the fasting."
How do I determine if the saliva I swallow afterwards is just the taste mixed with it or if its a bit of the moutwash mixed which is not allowed? Or can I be sure that when spitting it out at least 3 times it is fine whatever taste I feel?