Q: How do we know which Segulot are true?
A: Ha-Rav Chaim Kanievski once answered: "I only know that which is written in the Shulchan Aruch". Segulot Raboteinu p. 321. And see Ner Be-Ishon Laila p. 230).
Dove Relieving Himself
Q: What is the source that if a dove relieves himself on someone it is a sign that he will become wealthy?
A: There is none.
Throwing Out Pictures
Q: I heard that it is forbidden to throw away pictures. What then should I do with pictures I don't want to keep?
A: There is absolutely no prohibition against throwing them in the garbage (Most Gedolei Yisrael are not opposed to being photographed, but even those who are did not say that it is prohibited to throw away a picture. On the contrary, Ha-Rav Moshe Greenwald, author of Shut Arugat Ha-Bosem, was extremely particular not to be photographed, and would burn pictures with human images. But he hid away a picture of his mother since it would not be honoring his mother to burn her picture. Beit Yisrael Volume 8 p. 169. Tiferet Banim on Kitzur Shulchan Aruch p. 346).
Mezuzot and Shalom Bayit
Q: There are those who are selling very expensive Mezuzot which were not touched by a knife, claiming that they are a Segulah for Shalom Bayit. Is this true?
A: There is no source and it is exploitation. If a couple is having marital problems, they should turn to a marriage counselor (Ha-Rav Chaim Kanievski and Ha-Rav Meir Mazuz also said that they do not know of such a Segulah. Segulot Raboteinu p. 325).