These past 3 weeks have been pretty busy for the lab. Besides receiving 3,500+ new artifacts from the Republic, we had a visit from the National Geographic television crew. I am now happily dealing with the aftermath of this whirlwind by categorizing what artifacts need emergency stabilization and storage.
For instance, I have received many different forms of ceramics that need to be submerged in "de-ionized" water for up to 3 months to leach out the saltwater that has accumulated inside the object. By leaching out the chlorides we can stop deterioration of the ceramic object itself since it is very porous, but most importantly we can save the original glazing.
I use de-ionized water to soak these objects because tap water still has many natural chlorides in it. Deionized (DI) water has been put through electrical filters to take out all the salts.
Many of the ceramics still have marine life attached to them; the DI water doubly acts as a cleaner to the ceramics. After a period of soaking in the DI, the marine life will decompose and can be removed with a soft cloth with every water change.
I can figure out when the ceramics no longer contain salt water by testing the chloride content of the water. I use a compound called Silver Nitrate which when added to the vat water turns from clear to milky white. The milkier the color, the more salt still remaining in the vat. If nothing happens and the Silver Nitrate stays clear then the object is finished because it is no longer leaching salt.
Unlike ceramics and glass, leather is much more fragile. Although the process to conserve them is not very hard, it is time consuming.
To conserve the leather objects, I first soak them overnight and give them a quick rinse in DI water. I then take the leather (shoe in this case) and put it in a ultrasonic cleaner with a special solution that, among other things, keeps off unwanted bacterial growth. Acetone is also used as a rinsing bath at one stage. After the ultrasonic cleaning I will rub a glycerin-based solution I made on the object 4 times a day for 4 weeks. The object will then dry and be kept in an acid-free lining or container at the proper humidity.