Klucel G and E are non-ionic cellulose ethers. They feature a remarkable combination of properties which make them quite interesting to book conservators for use as consolidants. Klucel is soluble in water below 38 C, and insoluble in water above 40 C. It is also soluble in many polar organic solvents, including methyl alcohol, ethyl alcohol, and isopropyl alcohol (95%). It is insoluble in toluene, xylene, and trichloethylene. Klucel G and Klucel E are highly surface-active, and extremely flexible without plasticizers in films and coatings. Once prepared, Klucel G has a medium viscosity (2% solution: 150-400 MPAS) and a pH (1% solution) of 5.0-8.5; Klucel E has a lower viscosity