Another post on recycling glass. Hope it may be an inspirition to others.

How Glass is Recycled

The ideal environmental packaging medium
A glass container is made of the simplest ingredients - silica sand, soda ash and limestone. When used glass is crushed, it returns virtually to its natural state. It is inert, non-toxic and can't contaminate the environment even when disposed of in landfill sites. But there is also no reason why glass containers should ever take up valuable landfill space when they can be used, over and over again.
Glass is 100% recyclable - it can be recycled indefinitely to make new glass. The glass recycled in a jam jar today can be a juice bottle next month, then a coffee jar, a milk bottle, a pickle jar, a ketchup bottle, and on and on forever.
The goal should be the recycling of all glass food and beverage containers, so that the only new glass made is to meet increasing market growth for the products they contain.
Crushed recycled glass, called cullet, is combined with virgin raw materials (silica sand, soda ash and limestone) in the glass manufacturing process. Currently Consumers Glass is averaging a one-third recycled content in its new glass containers, up from 7% in 1988, with over 50% targeted for the year 2000.
Manufacturing standards for recycled glass
As in any manufacturing process, certain standards must be established and maintained in order for Consumers Glass to make maximum use of the glass householders put into the recycling stream through curbside or other recovery programs.
Since recycled glass is used as a direct substitute for raw materials, good quality recycled glass must be obtained - and this means used container glass which is colour sorted and doesn't include foreign materials such as heat-resistant glass cookware, ceramics, window glass, drinking glasses and light bulbs. All these materials are made of ingredients which are different from container glass and will cause problems in the glass making process.
To make maximum use of collected glass, the containers must be sorted to separate the clear from coloured glass. Only clear recycled glass can be used to manufacture new clear glass containers.
Consumers Glass contracts a number of processors with material handling systems to clean the glass of metal caps and paper labels and crush it into cullet. While the processor has the ability to extract bottle caps and lids, it is much better if the householder removes them. It is almost impossible, however, to take out other kinds of materials, such as ceramics and drinking glasses, once the recycled glass has reached the plant.
Foreign materials such as cookware, ceramics, window glass and light bulbs that go undetected can cause serious problems in the manufacturing process, damaging glass-making machinery as well as resulting in sub-standard glass containers which cannot be used.
The unbroken circle
The chart shown on the following page, titled, "The Glass Container Packaging System Model", shows how the recycling process works... from the manufacture of the glass container... to its sale and filling by a producer... resale to a wholesaler and retailer... final sale to an end user, who chooses whether to return it for refilling, to recycle or dispose of it.... and its recycling and final return to Consumers Glass to be made into a new glass bottle or jar.
The ultimate goal ... is to have an unbroken recycling circle. But this can only be achieved with the full support of the consuming public. They have the most important role to play in the recycling process -- putting out only those glass containers used for food and beverages for recycling. Consumers Glass is also seeking the assistance of recycling truck operators to identify and leave behind unacceptable materials during the collection process.
Glass not recycled into new containers is being substituted for other materials employed in a broad range of industries, including fibreglass manufacturing, in reflective paints, and as a replacement for aggregates used for various construction purposes.