Plastalina modeling clay is an oil-based clay, made by a variety of manufacturers, that's used extensively by animators and sculptors. The clay is non-hardening, coming in four versions of consistency. The soft version is useful for larger sculptures, medium clay used for busts and figure work, medium-firm for models and small objects, and extra-hard plastalina for work requiring a high level of detail. Even with the wide choices of firmness, you sometimes still need to soften the clay. This is often due to the clay being just a bit too hard to work with for your chosen sculpting style. Softening the clay can fix this issue, and be done either temporarily or permanently.
Things You'll Need
Temporarily soften your plastalina modeling clay by increasing the temperature of the clay. Turn on a hair dryer to a low setting and hold it 3 to 5 inches from the surface of the clay. Run the dryer over the clay's surface in a constant motion to gently heat the clay.
Kneed the clay vigorously to spread the heat throughout the clay evenly. The process of applying the heat and the motion of kneading the clay will soften it for working. Once the clay cools, it will return to its previous level of firmness.
Permanently soften the clay by adding a small amount of mineral oil. Rub the oil onto a small surface of the clay and then wedge the clay to disperse the oil throughout. Wedging requires that you take the lump of clay and throw it down hard onto a work bench. When on the bench, work the lump of clay by cutting it in half and turning one piece 90 degrees before placing it atop the second piece and kneading it together. Repeat the process several times until the clay is a uniform firmness. The more oil added, the softer the clay becomes.
Applying too much heat to plastalina may melt the clay completely.