If you have a prismatic glass light, then it is important that you take the necessary precautions when doing light maintenance or cleaning on them. First, make sure that you remove the light bulb before attempting to clean the fixture. You can simply use a soft cloth that has been dampened with mild detergent and/or water and wipe the glass. For better results, we suggest dismantling the fixture and soaking the glass in warm water before wiping it down and drying it with a towel.