It's Yom Kippur. Mr. Ploni is at home, praying the Amidah prayer with great emotion. He's crying, and his nose is dripping. Although it's a fast day, he wants to lick the snot off his upper lip.
If there's no tissue within arm's reach, may he do so?
If there's lots of tissue within arm's reach, but he wants to save time and/or money, or he prefers not to use a tissue, may he do so?