I do not know what “selling indulgences” means.
The Vatican is breath taking, in its beauty and history.
I had the opportunity to see it two years ago, unfortunately I went on a tour.....next time I will go by myself and take my time (if I get the chance that is).
Most people, even Catholics, don't know what indulgences are. Indulgences only remit the temporal punishment due to sins whose guilt has already been forgiven (through confession), by the merits of Christ, dispensed by Christ's Church, the minister of Redemption, under conditions prescribed by the Church.
Therefore, it is impossible for a Catholic to "buy his way into heaven."
In order to remit the temporal punishment due to a particular sin, the Church might prescribe prayer, fasting, or the giving of alms. During the period of the construction of the Vatican, this power was abused by some clergy, who offered indulgences in exchange for donations to the building of St. Peter's, although if such donations were done for the right reasons, and with the right intention, such donations would not be inherently evil.
The practice of ‘selling indulgences’, put very simply, was paying money to a priest or bishop so that certain sins would not be “counted against you”. Essentially, paying money so the church (and supposedly God) would look the other way.