Q. 1. My understanding of blessed objects is that when they are no longer used, they must be buried or burned. What about blessed Churches? If a parish is closing down, how is the Church unblessed?
A. 1. According to the Canon Law Society of America, their interpretation of Canon Law # 1222 §1 & §2 is that the “unblessing of a Catholic Church," as you call it, is a simple matter.
After consulting the priests’ council and others who may have a right to be approached regarding this matter, the bishop only needs to decree that the building is no longer dedicated or blessed. Consequently, it is no longer a Catholic church. Following this decree, the building may be sold to another denomination for worship, or sold for other appropriate uses, or finally be taken down if it is too old and beyond repair.
The related Canon Law are:
Canon Law # 1222 §1. "If a church cannot be used in any way for divine worship and there is no possibility of repairing it, the diocesan bishop can relegate it to profane but not sordid use.
Canon Law # 1222 §2. Where other grave causes suggest that a church no longer be used for divine worship, the diocesan bishop, after having heard the presbyteral council, can relegate it to profane but not sordid use, with the consent of those who legitimately claim rights for themselves in the church and provided that the good of souls suVers no detriment thereby."