Despite what preservation specialists have told you, there’s no oil in your fingertips. It’s true. I once visited a forensics lab and a fingerprinting expert told me there are no oil glands on the palm side of our hands. I checked into it and he was right. So after years of telling people they need to protect artifacts from the oils in their hands, I find out I’ve been wrong all along.
I haven’t been entirely wrong, though. Oil can be found in the fingerprinting process, but it’s most often forehead oil. This oil comes from sebaceous glands, which are everywhere on our bodies except the palms of our hands and the soles of our feet, and there are more sebaceous glands on the face and scalp than anywhere else. Because humans have the tendency to keep touching our own faces, we get oil on our fingertips. So, while we may not have oil in our hands, we usually have oil on our hands. This oil can cause permanent changes, especially staining, in various kinds of artifacts.
Despite the lack of oil producing glands, our palms do contain glands that produce a damaging substance. Fingerprints come primarily from the stuff in the eccrine glands. Eccrine glands produce sweat, or water and salt, and salt water is a corrosive mixture that can cause changes in various kinds of metal. While eccrine glands are found all over the body, the highest concentration is in the palms of the hands and soles of the feet.
Human skin is also covered in acid, the average pH of human skin being about 5.5.
This is only about as acidic as most bottled water, but it is still acidic enough to etch certain kinds of materials.
So, there it is. Despite our love for artifacts, our bodies are their natural enemies. Humans are natural producers of three threats to artifacts. Unless we can find a way to manipulate collection materials with telekinesis, we have to find a way to safely handle materials with our hands.
Gloves seem like an obvious answer, but wearing gloves is not always a good idea, especially when handling fragile items. Gloves, especially cotton gloves, make it difficult to feel what we’re doing to collection items, and that could result in some serious damage. Cotton gloves may also cause our hands to sweat and simultaneously wick the sweat from our hands onto the items we are handling.
This flowchart may help. Times you should definitely consider wearing gloves are when you are handling photographic materials, electronic media, and metals. You should also wear gloves to handle any item that may contain toxic materials, like arsenic. If you do wear gloves, avoid cotton and use snugly fitting latex or nitrile gloves.
When using gloves, they should be clean and should be changed as often as they become dirty. But everything else can be handled with bare hands as long as the hands are clean. I recommend the use of sinks and that hands be washed regularly, meaning every hour or so, when working with collection items. Once clean, hands should be kept lotion free. Also, don’t touch your face or hair, even if you’re wearing gloves.
Because I know that once you wash your hands your nose will start to itch, I suggest you purchase one of these tiny nose scratchers. Just kidding. If your nose itches and you scratch it, you’ll just have to wash your hands more often.