All perfect praise be to Allah, The Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad is His slave and Messenger.
If you notice that you have become pure by seeing total dryness, then you perform Ghusl and pray.
Some scholars are of the view that if a woman usually sees a white discharge after becoming pure (by total dryness), it is recommended that she waits for that white discharge until the ending time of the prayer during whose time she saw the total dryness, and when she sees it, she hastens to perform Ghusl and prays.
If after that you saw a yellowish discharge, then do not take it into consideration and do not consider it as part of your period (menses). This is because the yellowish discharge is not considered menses unless it is discharged with or after the discharge of blood (not after dryness), according to the view that we adopt at Islamweb.
Allah knows best.