What to do?

That is simply not true! The "spiritual" part of Alchemy was never secret; it was the experiments that were kept secret; to stop the curious "Nosey Parkers" interfering with the work. Alchemy did have a spiritual side, but mainly it was Science, especially medical science. Only that part was kept secret in Europe. Roger Bacon, mentioned above, was a Catholic Franciscan Friar in the 13th century. Hardly a secret!

You are right, that medical science was not secret.
But, many alchemical texts were veiled and it is hard to understand.
http://www.alchemywebsite.com/texts.html

And something about eastern alchemy
http://terebess.hu/zen/mesterek/Taoist-Yoga-Alchemy-and-Immortality.pdf

We might not have certain technologies today if it weren't for people who experimented with alchemy, it may be slightly dangerous but it isn't evil, its an exploration into the unknown. Someone might learn something nowadays that could better mankind as a whole, you never know.