There is much misunderstanding with regard to the longevity of plastics, especially outside in the elements. All plastics come from petroleum and natural gas. Sunlight, especially ultraviolet radiation, has a disastrous effect on most plastics. Some plastics, like polyethylene (PE) milk jugs, degrade quickly in the sun – in a matter of months. Acrylic comes from natural gas and is completely inert when in solid form so will not yellow when kept indoors. Due to the inherent UV stability of acrylic it can maintain its transparency after 30 years of outdoor exposure.