The Agnus Dei sacramental is one of the Church's strongest sacramental which can only be blessed by a pope. This great consecration of Agnus Deis take place only in the first year of each pontificate and every seventh year afterwards.
On the Wednesday of Easter week these discs are brought to the Pope, who dips them into a vessel of water mixed with chrism and balsam, adding various consecratory prayers. The distribution takes place with solemnity on the Saturday following. - Catholic Encyclopedia
The last known blessing of the Agnus Dei sacramentals was in 1964 by Pope Paul VI.
In a wonderful article by Charles Hugo Doyle, entitled "The Forgotten Sacramental," the author provides a summary of the special virtues of the Agnus Dei, as cited by Popes Urban V, Paul II, Julius III, Sixtus V and Benedict XIV, which include the following benefits:
They foster piety, banish tepidity, preserve from vice and dispose to virtue.
They cancel venial sins and purify from the stain left by grievous sin after it has been remitted in the Sacrament of Penance.
They banish evil spirits, deliver from temptation and preserve from eternal ruin.
They are a protection from a sudden and unprovided death.
They dispel fears occasioned by evil spirits.
They are a protection in combat, and have power to ensure victory.
They deliver from poison and from the snares of the wicked.
They are excellent preventatives against sickness and are also an efficacious remedy -- especially in cases of epilepsy.
They hinder the ravages of pestilence, of epidemics and infectious diseases.\
They quiet the winds, dissipate hurricanes, calm whirlwinds, and keep away tempests.
They save from shipwreck and the danger of lightning and floods. An anecdote is recalled here of Pope St. Pius V, who had recourse to this expedient when the Tiber was in flood and seemed likely to submerge the city. We are told that when an Agnus Dei had been thrown into the river, the angry waters at once subsided. - Agnus Dei Sacramentals and other relics
If you visit the parish of Santa Susanna (the English-speaking parish in Rome), you can ring the bell of the second sacristy and the sister will let you into the room which is a little gift shop. There you can receive, with a little donation, the wonderful Agnus Dei wax along with this informative brochure (with an Imprimatur from 1960). - Lost Catholic culture: the Agnus Dei wax
Since these sacramental have gone the way of the dodo bird (1964), how can there still be some of these wax sacramental available for the faithful?
The Catholic website Fish Eaters made an update on their Agnus Dei page stating the following:
Update: I've received an e-mail from a priest who was kind enough to take the time to inform me that the Holy Father issued Agnus Dei sacramentals during the Jubilee Year 2000. Wonderful!
My question is this: Is it possible to find a source (in print or online) that states definitively that Pope John Paul II actually blessed these wax tablets of the Agnus Deis during the Great Jubilee of the Year 2000?