Liquid latex, which is largely made of natural plant latex and ammonia, dries into a stretchy rubber that sticks to any porous surface it was touching when wet. It also sticks firmly to other rubber and makes a non-permanent but sturdy bond to skin. This makes liquid latex useful as a prosthetic adhesive and as a craft adhesive. You can use it to glue down fake costume pieces like noses or ears, or you can use it to make alterations and repairs to existing rubber pieces or rubber bald caps.
Dried liquid latex has an elastic texture and opacity that resembles human flesh, so it is often used to create a flesh effect. Sometimes this means making prosthetic body parts and facial pieces or entire face masks. Outside makeup applications, you can use latex to build prop pieces like fake body parts or fake dead animals, or to give synthetic fur a realistic-looking lower layer of "skin."
Makeup artists use liquid latex to create the effect of wrinkled skin without thick, molded prosthetic pieces. They do this by stretching the skin with fingers, applying a thin coat of latex to the skin, then letting it dry before releasing it. This creates a subtle wrinkling affect which, if done right, will look almost as natural as the real thing. Old-age stipple is a special form of latex formulated for success with this kind of application.
Liquid latex is sometimes marketed and sold as a means of creating customized, ultra-tight-fitting rubber clothing. To use, simply paint it on your body. When it dries, you will be encased in a form-fitting latex body suit. This type of latex is made in a variety of fashion colors (whereas theatrical latex is generally beige) and designed to dry with a shiny finish.