What is the ruling regarding these discharges that come to me outside of my menstrual period, and are they considered استحاضة (istihadah - irregular vaginal bleeding) that obligates me to perform ablution for every prayer and to take precautions, or not? What is the nature of the yellowish and brownish discharges, and are they considered impure? And does musk (used for purification) remove these discharges?

Yellow discharge (ṣufra) differs from vaginal moisture. Normal vaginal moisture is pure (ṭāhir) but invalidates ablution (wudūʾ). As for yellow discharge, it is impure (najis), and if it is not connected to blood, it is not considered menstruation (ḥayḍ) except during the time of menstruation. If the yellow discharge is connected to blood, then it is considered menstruation, and one must perform a ritual bath (ghusl) after its cessation and seeing purity. If the yellow discharge returns after purity, it is not considered menstruation, and one must take precautions against it. If it is continuous or irregular, one must perform ablution for each prayer after its time has entered. If the questioner suffers from obsessive thoughts (waswasa), she is permitted to follow the easiest of the madhhabs (schools of thought).