"Some forms of Yoga recommend "emptying one's mind.  But this recommendation is antithetical to what the Church teaches."

What spirituality books [Catholic] have you been reading?  Centering Prayer [a valid and approved method of contemplation] highly recommends freeing the mind from distractions and emptying it.  Do you even know the difference between meditation and contemplation?

In Benedictine spirituality, often beginners are taught to quietly hum one musical note to keep the mind clear.