Sandstone markers, in particular, are susceptible to irreversible damage if improperly cleaned. Aggressive cleaning methods are never encouraged by preservationists. Thorough rinsing is essential and may necessitate hauling large quantities of clean water to the work site. The use of improper cleaning materials and practices can cause serious and irreparable damage to gravestones. Attending cemetery restoration workshops are one of the best ways to learn more about stone repair techniques.
Every situation is unique.
The condition of the stone, the type of break involved, the nature of the stone, etc. are all essential factors in determining how best to proceed to repair a broken marker. Resetting of markers as required. When possible, it is desirable that grave markers be restored to a vertical position. Flat markers of the type used for Civil War veterans were usually set directly into the ground. Restore them in the same manner.