Wite-Out may be removed from plastic by using a combination of WD-40, mild dish soap, a scouring cloth and paper towels. Start by spraying WD-40 over the Wite-Out and allow it to sit for a few minutes to soak into the stain.
Use a cloth to rub the Wite-Out from the plastic. More WD-40 may be used as necessary, however, make sure that there is ventilation for the fumes if working in an enclosed space. Once the Wite-Out is scoured from the plastic, use the paper towels and dish soap to wipe away any excess WD-40. Wipe away any lingering dish soap suds with a damp paper towel, and allow the plastic to dry.
Although the exact composition of WD-40 is unknown, it is widely accepted that it contains a penetrating oil and a volatile hydrocarbon. A penetrating oil is a low viscosity fluid, which means that the fluid has little resistance to changing its shape. In the case of WD-40, this characteristic allows the oil to seep into seams between two objects and loosen, or lubricate, the bond between them as it does with Wite-Out and plastic.