First, virgin glass is cheap to produce. Thus, the added cost of shipping used glass back to be recycled can make recycling out of the question economically. We are lucky in Northern Colorado. A large glass recycling plant (Coors Bottling in Golden) is relatively close by.

The second problem is the extremely high standards of glass manufacturers. Any foreign material that makes it past the screens in the recycling plant can cause imperfections in drink bottles and become a safety threat to consumers.

"Home recyclers can help decrease such contamination by using extra care in preparing glass for recycling, " said Cheryl Kolus, environmental educator with Larimer County Natural Resources. "Keep gravel and stones from accidentally getting into your bin, and be especially vigilant to prevent ceramics, pottery, light bulbs, and mirror shards from being mixed with regular bottle glass. Definately DO NOT put syringes into bottles! Don’t leave bottle caps or metal lids attached. Removing those pesky aluminum rings to which twist-caps are attached would help, too."

Pyrex or ceramics have varying chemical compositions and melting temperatures. They create flaws or bubbles like those pictured above, and the new glass container cannot be used.

In the past, Coors rejected some loads of glass from the Larimer County Recycling Center due to contamination. This was discouraging, and it forced the County to make the difficult decision to discontinue shipping glass to Coors. Receiving only $15 per ton for mixed-color glass, it was too costly to take it to Golden, only to risk having to bring it back.

The County installed an "air classifier" to the conveyer-sorting belt at the recycling plant that helps rid the glass of contaminants such as paper and plastic, improving quality.

The good news is that the recycling center has begun a pilot program to once again take mixed glass to Coors. The first load was taken to Coors on July 17, 2003.