Paper is a thin sheet material produced by mechanically and/or chemically processing cellulose fibres derived from wood, rags, grasses or other vegetable sources in water, draining the water through fine mesh leaving the fibre evenly distributed on the surface, followed by pressing and drying.

It is a versatile material with many uses, including printing, packaging, decorating, writing, cleaning, filter paper, wallpaper, book endpaper, conservation paper, laminated worktops, toilet tissue, currency and security paper and a number of industrial and construction processes.

Coffee filters are made from filter paper. There are many debates about which filter is better: bleached or unbleached.
Unbleached filters are made from raw paper, therefore more natural and much more environmentally friendly.

Bleached filters are whitened with Chlorine or oxygen. Unfortunately, bleached filters are not as good for the environment. First, there is an added step to the manufacturing process. Second, these filters with the bleach can pollute the environment when they are discarded, even though there is only a very small amount of bleach used. Oxygen-based bleaches are the better option here as well, as oxygen is much more environmentally friendly compared to chlorine.