Having sparkling clean artifacts allows us to do such things as properly identify this hand painted underglaze pearlware, label, and mend it while keeping track of each piece.
by Daphne Ahalt – CART Assistant Lab Director
This week’s blog post is a review of the procedures used in the CART lab to wash artifacts recently excavated in the field. The word “wash” is a bit misleading because not all artifacts are washed in water, so we will also discuss materials that require dry brushing. Please note that different labs may have different artifact cleaning methods and materials which they use to wash.
In the CART lab, each brown bag of artifacts is a single Field Specimen (FS) with its own FS number. Each FS is related to a specific provenience – the horizontal and vertical location of an artifact or feature. The provenience describes where we found an object in relation to other objects on a site, and is an important tool when interpreting the site’s history. Only one Field Specimen bag is cleaned at a time so that artifacts do not get mixed in with those from another FS.
The proper tools for cleaning are gathered before starting. For the CART lab this includes: a sheet of white paper, two washing tubs filled halfway with plain water (no chemicals or cleaning solutions!), a mesh strainer, 2 soft bristle toothbrushes (1 stays dry), a sponge, and an unused drying rack with some wooden dividers. The person washing will also use a pencil, a pair of scissors, and the project wash log located near the washing station.
Thanks to our great volunteer team, CART usually has volunteers available to wash our artifacts. The volunteer washing the artifacts begins by placing the sheet of paper on their work surface. They will then enter the FS number, their initials and the date into a log. This log helps track what was washed, when it was washed and who washed it. The washer then places the artifacts on the white sheet of paper, cuts out the information contained on the front of the artifact bag, and places it on the drying screen. The artifacts will be placed on the drying screen with that paper bag cut out insuring that the FS information travels through the process with the associated artifacts. The volunteer washer then separates the artifacts into piles of artifacts that cannot be cleaned, those that can be washed in water, and those that are to be dry brushed.
“Do not clean” artifacts include those that are extremely delicate, such as bone that is falling apart, carbon and soil samples, brass buttons, and items set aside for special analysis. If the washer has any questions, they are encouraged to ask a staff member for help. The person washing will then place the “do not clean” artifacts directly on the drying rack.
Dry brushed artifacts include metal objects. Depending on the artifact’s durability, bone and shell artifacts should also be dry brushed. Once the artifact has been brushed clean, the person washing will place it on the drying rack with the other artifacts from the same FS number. Again, it is extremely important for the person washing to keep artifacts from one FS separate from artifacts of a different FS so that no mixing of provenience occurs.
Prehistoric ceramics are often cleaned with a wet sponge. Most all other artifacts, such as glass and historic ceramics, can be submerged in water and scrubbed with a wet toothbrush. It is important for the washer to clean the edges of glass and historic ceramics so that the color and paste can be clearly identified by staff. It is also important for the washer to make sure all artifacts are completely clean because many of the items will need to be labeled with identification numbers. Labels will not affix to dirty surfaces. Once cleaned, the washer will once again place the artifact on the drying rack with the artifacts from the same FS and the associated brown bag cutout containing the provenience information.
The person washing will repeat the process for each Field Specimen bag and make sure the FS bags are clearly separated with dividers. Enough space is placed between different FS numbers to keep them apart in case a drying screen gets bumped. The washer cleans up their area when finished; this includes rinsing all tubs, toothbrushes, mesh strainers, etc. and placing them on the drying rack next to the sink. Washers will then wipe down the work surface, and if needed, sweep the floor around their work area.
We appreciate our volunteers and all the work they do! Join us by signing up for our next Volunteer Orientation at https://www.fairfaxcounty.gov/topics/volunteering .