The variety on contamination that an object can acquire could be by exposure to insects, sediments, flyspecks, roaches, moisture, dust, mildew, adhesives, pigments, acid framed materials, arbitrary interventions, and other invisible particles of the environment.

Before a piece to be worked on successfully, all the contamination needs to be removed. Here comes the craftsmanship and experience of the conservator to know how to stop this deterioration and achieve a stable piece that it can be worked on.

This process is also used as preventive conservation. It is of utmost importance to have a material that is not contaminated in order to apply successfully the conservation procedures.