Purity: Purifying Narrow-Mouthed Utensils Licked by a Dog
Practical Laws of Islam as per the teachings of Ayatullah Sistani
Ruling 145
If the mouth of a utensil that a dog has licked is narrow, soil must be poured into it and the utensil must be shaken vigorously so that the soil reaches all parts of it; after that, it must be washed in the manner mentioned above.
-Ayatullah Sistani, Practical Laws of Islam, Purification (Taharah)