Perhaps the most important part of an archaeological excavation is the preservation of data. A long term strategy is needed in order to safeguard the future of the archaeological material which, must be well defined before the excavation of the site commences. Conservation of the artefacts begins on the seabed during their excavation. Methods and techniques utilised should facilitate future conservation on the surface and in the laboratory. All conservation and registration that can be done on the surface (because of limited dive time) should be avoided on the bottom. Once out of the water, the object´s contact with light, air (oxygen), and increasing temperature should be reduced as much as possible.
Immediately after excavation every find is registered i.e. given a number, drawn, measured and described. After registration artefacts are placed in plastic bags and kept wet with water from the Baltic, away from unecessary contact with light and air. Artefacts are then taken to the lab for conservation and sampling.
All artefacts are then photograhed with a scale. Artefacts are de-salinated and depending on their compostion either dried out slowly using special processes, or put into PEG (polyethylene glycol) and then freeze-dried. Textiles are conserved by other methods.