Once we visited the Monastery of Vella, and entered an old church with frescoes. We were amazed at them, while [St. Porphyrios] disappeared into the holy altar. I was by myself in the one aisle, and the rest in the other. In a short time I sensed a fragrance...The church was old and did not function anymore. As time passed, the fragrance got stronger. I looked around. I noticed that it was the strongest towards the holy altar. "Ah, I understand," I thought, "The Elder lit a charcoal and put on some incense."
When he exited the altar, I told him unprompted: "That charcoal you lit, Elder, it smells very beautiful."
He looked at me with a strange smile. "No," he told me, "I didn't light anything!"
Later, he told us: "When I enter the altar of a church, however, I pray. And I sense all of the prayers that had occurred there. This happened a short time ago in the altar. I prayed, and A. sensed it. Don't we say that prayer rises to God like incense?"
At St. Ierotheos I experienced the same thing. There, as soon as we exited the church with the Elder and got in the car and drove away from the church, there came a wave of fragrance. The Elder said with a smile, without anyone asking him: "This was a special blessing of the Saint."
(amateur translation of text from source: Άγιος Πορφύριος http://www.porphyrios.net/?p=2345)