Cellulose fibers formed by high purity cotton linters. The sample to be filtered can be mixed with the cellulose fibers, forming a suspension that favors the flocculating effect. It can also be used to form a pre-filtration bed in the funnel. Of course, it must be used in combination with a slow speed filter paper. Depending on the ash content of cellulose fibers,
these can be quantitative (<0.1%)