Printing papers published in between 1950's and 1990's were treated with three methods such as distilled water washing, CaCO 3 solution washing and methyl cellulose solution coating for improving their conservational properties. Accelerated aging with 80 o C and 80% RH for 14 days was applied to the testing papers. Results showed that distilled water and CaCO 3 washing kept increased pH even after accelerated aging, but did not improve folding endurances for 1950's-60's papers. Methyl cellulose treatment did not increased pH of the old papers, but increased folding endurances remarkably for 1950's-60's papers even after accelerated aging. It suggests that methyl cellulose treatment after CaCO 3 washing should give improvements both in pH and folding endurance.