A lot of movie theaters use the Real-D system. The glasses are handed out in plastic pouches before the film, and then collected in a recycling box afterward. These glasses are then shipped to a processing facility in Los Angeles, where they are professionally cleaned in a proprietary washer. According to Greenopolis, this facility processes more than 700,000 pairs of glasses each day. Slate reports this recycling program has been in effect since November 2008.
Most IMAX theaters have a specialized washing machine which they keep on-site for cleaning 3D glasses. This machine is a requirement for IMAX theaters for use of the IMAX brand. The glasses sterilizing machines functions a lot like a commercial dishwasher, like what you would find in any restaurant. The glasses are re-washed and handed out before each showing. Each pair of IMAX glasses can be reused about 500 times.
Glasses made by Dolby Studios are actually washed in a commercial-grade dishwasher. Unlike IMAX glasses, which use a similar machine, these machines are typically designed and used for cleaning food off of plates, but the temperature can be set lower when cleaning 3D glasses so that the plastic frames and lenses don't melt. They can use standard dish soap to clean the glasses, but this does mean that the cleaning quality may vary from theater to theater.
Some XPanD glasses use a shutter system, which means they have battery packs and sensors which would be damaged by a cleaning process in a machine. For many theaters which use XpanD glasses, they have to hand-wash the pairs of glasses after each viewing. At some theaters, instead of cleaning the glasses themselves they hand out disinfectant wipes with the glasses for the customers to do the cleaning themselves.