Archaeology at Freshwater Sites (Part III)

General Guidelines for Conserving Objects Excavated from Freshwater Sites

• Do not hesitate to ask for professional advice. Contact the John and Martha Daniels Laboratory (JMD) at the Minnesota Historical Society or a professional conservator in your area; telephone, (612) 297-5774. The American Institute of Conservation (AIC) in Washington, D.C. has a computerized referral service that lists AIC members who consider themselves qualified in specialized fields; call (202) 452-9545.

• Have a plan. Anticipate what types of objects and materials will be brought up. Plan to have the funds, equipment and supplies necessary to properly store and stabilize the objects.

• Know where the objects will end up for long term storage and/or exhibit. Contact the repository, if known, for their guidelines for storage. Make adequate provisions for proper storage supports and materials.

• Good archaeology is proactive. Contact a conservator before proper object care becomes a major problem.

• Provide adequate security for the objects, especially if they are in outdoor holding tanks.

• Take water samples and object materials to a conservator for testing, if at all possible. This will help establish the condition parameters and help to design proper treatments. It is usually easier to send samples than the objects to an out-of-town conservator.

• Keep wet materials wet. Try to maintain the objects’ environmental equilibria.

• Monitor the water quality in the holding tanks regularly for mold growth.

Note: Electrolysis is usually not necessary for metal stabilization. “Traditional” methods for treating marine objects are not always directly applicable to objects from other environments.


Trade axe head found in 1960 at Horsetail Falls with the nested kettles. The steel blade edge has annealed to a wrought iron body. Wrought iron and steel is stable in fresh water

Some Definitions

CONSERVATION is the profession that is devoted to the preservation of cultural property for the future. It includes examination, documentation, treatment, and preventive care, supported by research and education.

TREATMENT is defined as the deliberate alteration of the chemical and/or physical aspects of cultural property, aimed primarily at prolonging its existence and preserving as much inherent information as possible.

STABILIZATION denotes treatment procedures that are intended to maintain the integrity of cultural property and to minimize deterioriation.

RESTORATION denotes treatment procedures that are intended to return cultural property to a known or assumed state, often through the addition of non-original material(s).

A CONSERVATOR is a professional whose primary occupation is the practice of conservation and who, through specialized education, knowledge, training, and experience, formulates and implements all the activities of conservation in accordance with an ethical code such as, but not limited to, the AIC Code of Ethics and Guidelines for Practice.