I heard a story about a skeptical visitor to Shirdi whose mind was changed. Can you tell me about Boss Dharamsee and the grapes?

Certainly. This story from Chapter 35 illustrates how Baba worked with a person's individual doubts. Boss Dharamsee arrived in Shirdi with a 'clinical scrutiny' and was initially unimpressed. When Kaka offered grapes with seeds, Baba began distributing them. Dharamsee disliked this variety and internally questioned Baba's sainthood for offering them to him, especially since he was also concerned about eating them unwashed. However, when Baba insisted he eat them, Dharamsee discovered they had miraculously become seedless. This direct experience shattered his skepticism and ego, and as the text says, 'love for the saint was born' in his heart.