Parrots in general do not respond to 'punishment' type of behavior correction, however if Elmira is bonded to you, you could try the "shunning" type of correction. WHen she nips the ear or glasses, a firm "NO BITE !" and IMMEDIATE removal to a neutral place, like a handy chair back and then turning your back to her and ignoring her for a minute can work (over time). It must be done immediately when the nip occurs, and she must be totally ignored ( no eye contact at all, no talking about her ) for no more than a minute. Any longer and the lesson might not be understood by the parrot. THis works well but only if she is bonded to you. Dont put her back in her cage, that can become the birds way of getting you to put her back. Everyone in the family must observe this treatment and it must be done 100% of the time when nips occur. It does not work well if Elmira is flighted and she can just fly off the chair back to where ever.
I do agree that an untrustworthy parrot should not be on a shoulder, especially large ones like a macaw, as you cant see their head and eyes, and cant see the classic signs of an impending nip. Body language in most parrots can signal the intent on nipping and biting, but you need to see the whole parrot to observe it.