1891 (rev. ed.) VII. 739/2 The process has..been brought extensively into use of late years, old newspapers and books forming much of the material for repulping.
2003 (Nexis) 2 Dec. (Headstart section) 104 Paper is collected, sorted, and then pulped. Small amounts of caustic soda, sodium sillicate [sic] and hydrogen peroxide are added to help with the repulping.