There are no sanctioned tattoo parlors in prisons, but inmates often get inked while in the big house. Tattoos are a signifier of identity, which is particularly important in a place where you are an assigned number, and all your possessions can be taken at a moment's notice. But it has never been easy. In earlier times, any sharp object was used to shove ink under the skin. Now tattoo machines are used, but they must be cobbled together from what is available to inmates.
Prisoners take apart beard trimmers or CD players to get at the tiny motor, which they can adapt to make the tattoo needle go up and down quickly enough. (Tattoo artists who use beard trimmers can quickly put the shaver back on and trick guards searching for contraband.)
The needle itself is often made from a metal guitar string split in two by holding it over an open flame until it snaps in half, creating a fine point. The springs inside gel pens can also flatten into needles.
One former prisoner who now runs a tattoo shop said he used to make black ink by trapping soot in a milk carton placed over a burning pile of plastic razors or Bible pages. He would mix the leftover ash and soot with a bit of alcohol (for hygienic purposes). To get color, some inmates use liquid India ink that family members buy from arts and crafts stores.