How does the lost item-charity to Rebbi Meir Baal Hanes work?

Question

I was told that if a person lost something they should turn a cup (or pot?) upside down say a tefillah and give tzedaka to rebbi meir baal hanes.

1. what is the source for this?
2. is it halachically permissible?
3. why do we need to turn a cup upsidedown?
4. what is the actual text of the tefillah?
5. must the person who lost the item perform this themselves or can others do it for them?
6. are the steps of the rite as listed above accurate?
7. does the order matter (i.e. can I give the charity first instead)?
8. are there other similar rites in judaism for recovering lost items?
9. can you perform this rite for multiple lost objects all at once?

Answer 1

The Birkei Yosef (Yoreh De'ah 203:4) defends the practice to swear donate money to tzedakah in the name of Rabbi Me'ir if he makes a certain profit. However, he says it's better to donate the money before. (He doesn't talk about Rabbi Me'ir's connection with lost items.)

Rabbi Joshua Waxman addresses some of these issues in a blog post. He concludes: "This is magic; this is superstition; this is darkei Emori. ... If I were to reinvent this segulah, I would insist it be said in English, or whatever the first language of the speaker is. I would remove Rabbi Meir. Instead, after the derasha from Rabbi Binyamin, I would put in something like: God of Abraham, God of Isaac, God of Jacob. I need help finding this, and I know all is in Your Hands. Please, open my eyes and help me find this lost item."