Papillomas are viral warts that occur with some frequency in birds. My favorite papilloma treatment is to use Gaia Thuja oil (this is an oil, not a tincture, which contains alcohol and will sting). Thuja is a potent remedy for papillomas. I place one drop on my finger and rub this onto the papilloma twice daily for as long as it takes to see improvement.
Note that thuja should not be consumed internally, so I use care if I think the bird is ingesting the oil. However, I have not yet seen any problems from using the Gaia oil.
Disclaimer: These statements have not been evaluated by the Food and Drug Administration, or by any veterinarian. All information, including any product or technique mentioned, is for educational purposes only. None of the information is intended to diagnose or treat any disease.