Use soap and water to clean the deceased person's fingers. Remove silt, grease and dirt with a child's soft-bristled toothbrush if the skin is firm. Brush gently and use strokes that follow the finger's ridge design so you access the depressions. Apply xylene, a chemical that removes oils and fat particles, if necessary. Use a cotton swab if the skin is not firm enough to withstand the toothbrush.
Straighten the fingers by "breaking the rigor." Hold the hand of the deceased person with one hand. Grasp the finger you are straightening with the four fingers of your other hand. Place your thumb on the knuckle of the deceased person's finger and force it straight as if using your thumb as a lever.
Use the spoon-shaped tool for holding the cut fingerprint squares or strips to print the deceased person's fingers if you are unable to straighten the fingers. Resembling a gouge without a sharp edge, this tool has a concave end, a clamp to hold the squares or strip and a handle. Do not roll but apply gentle pressure to the inked finger with the tool.
Use a hypodermic syringe to inject water or glycerin into a deceased person's finger if the skin has become dry and wrinkled. Insert the needle at the top joint of the finger and up to the fingertip. Keep the needle just under the surface of the skin. Inject the fluid until the finger's flesh rounds enough for inking and printing. Inject the tissue builder at other points in the finger if one injection fails to completely fill the finger bulb or the top section of the finger.
Use a scalpel if you are unable to break the rigor mortis with your hands. Cut along the second joint on the inside of each of the deceased person's four fingers. Straighten by using force. Make a deep cut between the index finger and the thumb in order to straighten a bent thumb.