A device that protects the inner surface of pipes from rust is disclosed. This device is especially useful for pipes provided with threading and a thread guard at their threaded ends to form an airtight seal. The device comprises a holder that can be inserted in the pipes on which a number of receptacles are attached at intervals. The receptacles are filled with a drying agent or dessicant and are made of a moisture permeable material. A moisture indicator may be placed in the base of the thread guard.