Rav Elimelech Biderman tells the following story in Be’er HaParsha:
Some tzaddikim have the custom to cast items of clothing – even including their yarmulkes – into the flames of the Lag B’Omer bonfire. Once, a Yerushalmi Jew approached Rav Dovid Tzvi Shlomo to get help for his sick son. The boy had long ago ceased communicating normally; in fact, he no longer spoke at all and he seemed to have lost his mind. He had formed the troubling habit of constantly throwing off his kippah and walking around bareheaded, to the shame and embarrassment of his family. The Rebbe was about to depart for Meron and he asked them to join him.
The poor father suffered continual shame along the way from the troubled boy, who frequently ran off and had to be chased after and brought back. Finally, the group arrived in Meron. When the traditional bonfire was lit on the roof of the tzion of Shimon Bar Yochai, the Rebbe approached the young child, grabbed the yarmulke off the boy’s head, and tossed it into the flames. No sooner had he done so than the child covered his bare head with his hands and began to yell in Yiddish: “A kappel, a kappel!” (“Give me a kippah [to cover my head]!”)
Everyone present was astounded. This child, who had long ago ceased speaking and acting in any normal fashion, was suddenly talking! Furthermore, he was asking for a kippah to cover his head – after years of habitually throwing his kippah off! From then on, he was cured.
