What is the ruling on natural yellow discharges that exit a woman, and do they invalidate the prayer or not?

The treatment for obsessions is to ignore them and not pay them any attention. By disregarding them, you please Allah and obey His command, whereas by responding to them, you follow the footsteps of Satan. You are not required to perform ghusl (definition) for semen unless you are absolutely certain that it is semen necessitating ghusl. You are not required to perform ghusl for normal yellowish discharge; rather, only wudu is needed, unless it is menstrual blood. If you are uncertain whether the discharge is semen or something else, you may choose and assign it the ruling you prefer.