Conditions Survey and Preservation Plan

For Pioneers and Soldier Cemetery

MacDonald & Mack Architects, LTD




Appendix C


Any cleaning work done to markers and piers has the potential to hasten deterioration of the historic stone.  Therefore, markers should be cleaned only as often as is necessary, when vegetation appears in the joints or when the stones are too blackened to read.  Piers should be cleaned with the same frequency.


In most instances, this means light scrubbing with plain water and a nylon or tampico brush.  If soil is particularly difficult to remove, a 1:4 mixture of plain ammonia to water can be used.  To remove vegetation attached to mortar joints or seams, wet the joint completely and scrub lightly with a nylon toothbrush.  If the vegetation still cannot be removed, use of a wooden tongue depressor is acceptable.  The marker should be completely saturated with water before, during and after cleaning.[1]


Various chemicals can be used to facilitate the cleaning process, but given the wide variety of stone types present in the cemetery and the incompatibility of some stones to acidic or alkaline cleaners, it would be wise to avoid their use in favor of plain water.  Poultices as well should be avoided as they function due to the presence of a cleaning agent.  Steam cleaning of markers is acceptable, but such a method is expensive and most likely cannot be conducted by a volunteer or untrained conservator.[2]  Products such as bleach, muriatic acid, wire brushes and pressure washers should never be used to clean markers, as they could discolor or abrade stone.[3]


In addition to avoiding the chemicals and methods listed above, care should be taken to not clean markers prior to a frost.  Water trapped in stone can freeze and expand, possibly causing the marker to crack.[4]  Also, markers that have been repaired  before should be left to be cleaned by a conservator, as soaking the stone with water or putting pressure on the marker may cause the repair joint to lose strength.  Stones that are clearly deteriorated or in danger of cracking should be left for a conservator to clean for similar reasons.[5]  Finally, in no case should a marker be sealed with waterproofing material after cleaning is complete.  Sealing the stone will only prevent moisture that has wicked into the stone from surrounding soil from escaping.  Spalling and cracking will likely result as the trapped moisture expands and contracts with the freeze-thaw cycle.[6]

[1] Strangstad:14.

[2] Mack: 5-7.

[3] Strangstad:14.

[4] Mack:7.

[5] Strangstad:14.

[6] Ibid.:17.