well where I am, pure food grade lye is common place in supermarkets..

as for ammonia, well, it should evaporate completely so if SWIY's parrot felt some ammonia taste, he probably just didnt evaporate/dry well enough

In any case for rue I think sodium carbonate is better because of being ,easier and safer to deal with, no danger of overshooting the pH, , spills, etc... So I would rather recommend using sodium carbonate next times..  but since the thread was about someone that already used the lye, I was just explaining that its not necessarily a problem