This product is primarily meant to clean mineral deposits and hard water stains from the interior of your dishwasher. One envelope is enough to remove a multitude of nasty mineral stains and buildup inside my dishwasher, which makes my dishes and glasses come out cleaner and with fewer spots. As if that isn't enough, Glisten can also be used to brighten whites in the laundry, clean stains in coffee pots, and to remove mineral spots stains, and soap scum from tubs, sinks and toilets.
The great thing is that this product is safe to use with septic systems, because it's environmentally friendly. It uses natural food acids to clean, so it won't harm plumbing or fixtures.
The $4.50 price tag is for 2 envelopes. I have been using Glisten monthly for several years, and it's kept my dishwasher and bathroom fixtures in great condition. I absolutely recommend it!