from the cotton by any satisfactory means such as filtration centrifugation etc the cotton is then rinsed with neat solvent and allowed to air dry the treatments described effectively eliminate endotoxins from the fiber or dust as measured by limulus amoebocyte lysate gelation 95 ethyl alcohol is used because it is an azeotrop and can be recycled it is also economically available as a commercial 95 grade an effective range of 95 alcohol to sodium hydroxide or hydrochloric acid is 270 400 1 effective range of temperature is 60 u00b0 to 80 u00b0 c ratio of dimethylsulfoxide to cotton is 30 100 1 on a wt basis a ten gram sample of cotton was immersed in 500 ml of 95 ethyl alcohol containing 1 0 g sodium hydroxide that had been heated to 60 u00b0 c the cotton remained in the solvent for one hour then the solvent was removed from the cotton sample by vacuum filtration the cotton sample was then rinsed with an additional 500 ml of neat solvent and allowed to air dry the results of the limulus lysate gelation test were as follows endotoxin in ppm was 1 0 which was 11 of the original value for the untreated cotton a ten gram sample of cotton dust was immersed in 500 ml of 95 ethyl alcohol containing 1 0 g sodium hydroxide that had been heated to 60 u00b0 c the dust remained in the solvent for one hour then was filtered through a buchner funnel to remove excess solvent the dust sample was then rinsed with an additional 500 ml of neat solvent and allowed to air dry the results of the limulus lysate gelation test were.