Two neutralising compounds were tested for their efficacy in slowing down the degradation of acid papers. Alkoxy magnesium alkylcarbonates such as methoxy magnesium methylcarbonate, raised the paper pH value and was very effective at reducing acid deterioration. Diethyl zinc did not increase the pH so much but was quite effective at slowing down acid deterioration, even at a concentration as low as 0.5% on the paper. Ageing of the papers was carried out at 80 c and 80% rh. References, graphs.