diatomaceous earth maybe?
I say NO..to DE.
Everyone has their own thing..mine...easy peasy. I go to the pet store, and I buy the mite spray for leg mites. Yep! It works wonders .. I spritz some on the bum, thigh area, back, front, back of neck, under wings, chest, and in front of neck. Easy! Don't have to wait on eating eggs either.
Now..inside of ears? I've never had that problem..never did the spritz inside the ear. Maybe a Q-tip with some on it..might work.