1. Remove mud spots. (1) Hot water method: put the pages in a large porcelain dish containing about 70% water, then carefully scrub the mud spots in the water with a brush or absorbent cotton ball, then put them in another clean water dish for cleaning, then suck out the water on the pages with absorbent paper after washing, and finally dry them. (2) Alkaline water method: If the pages are seriously dirty, you can put the pages on the board, then rinse them from the top with hot alkaline water with the concentration of 1 ~ 2%, and finally rinse them with clear water for several times and dry them. 2. Remove oil stains. Solvents such as benzene, gasoline, ethyl acetate and carbon tetrachloride can be used to remove animal oil and mineral oil spots; Solvents such as carbon tetrachloride, ethyl acetate, the mixture of carbon tetrachloride and ether 1: 1, the mixture of carbon tetrachloride and chloroform 1: 1, the mixture of benzene and ether 1, pyridine can be used to remove vegetable oil stains. When operating, first put a piece of filter paper under the oiled paper page, and then squeeze the oil stain with a cotton ball dipped in solvent. After the oil is dissolved, it will be absorbed by the filter paper under the page. After the filter paper absorbs oil, it will be replaced with clean filter paper. Turn the page over after removing one side of the oil stain, remove the oil stain on the other side of the page in the same way, then rinse the page with clear water and finally dry it. 3. remove mildew spots. Mold spots are black, gray, brown and other colors, which are difficult to remove. Mild mildew can be wiped with 2% chloramine T, 75% ethanol, 2% formaldehyde and other solutions. In operation, the pages are lined with absorbent paper, dipped in the above solution with a brush to rub off mildew spots, washed with clear water after removing mildew spots, and finally dried. If the mildew spot is serious and the area is large, it needs to be dipped in water for bleaching. Commonly used bleaching agents include bleaching powder solution (concentration 0.5 ~ 1%), potassium permanganate solution (concentration 0.5%), chloramine T solution (concentration 2%), sodium chlorite solution (concentration 3%) and so on.

In operation, the treated page is soaked in water for a while, then soaked in bleaching solution for about 15 ~ 30 minutes, then washed with water for 10 ~ 15 minutes, and then taken out and dried. 4. Remove the ink. The blue-black ink spots can be treated with 0.5% potassium permanganate solution for about half an hour, and then the purple-gray color can be removed with 0.5% sodium bisulfite solution. It can also be bleached with 3% oxalic acid solution, washed with water and dried. 5. Remove wax spots. (1) blanching method: firstly, scrape off the wax mark with a knife, then put a piece of filter paper on the stain, iron it with an electric iron (the temperature is kept at 40 ~ 50℃), and move it frequently until the wax mark is not visible on the filter paper. ② Chemical method: choose solvents such as benzene, toluene or ether. When operating, first buckle the stained page on the filter paper, clamp a cotton ball with tweezers, dip it in solvent and wipe the wax spot on the back of the page. After solvent dissolves wax, it will be absorbed by filter paper. When wiping, always replace the cotton ball and filter paper. 6. Remove rust spots. Select 5% oxalic acid solution, and the operation method is the same as that of removing oil stains. 7. Remove paint spots. Solvents such as acetone, ammonia water, methanol and pyridine are selected, and the operation method is the same as removing oil stains. In the process of decontamination, we should also pay attention to the following points: 1 Before decontamination, we should test the fastness of handwriting. The method is: cut the pages with the same handwriting on the waste book, drop a few drops of prepared detergent on the filter paper, immediately align the solvent drop on the filter paper with the text and squeeze it hard. If there are no ink marks on the filter paper, you can use detergent; If there is ink, you can't use it. 2. After the decontamination operation is completed, it is generally necessary to rinse with water, preferably distilled water. 3. After decontamination, don't dry it in the fire or sun, but put it in a cool and ventilated place. It is best to use the low-temperature drying method, that is, put the wet pages in the freezer (or low-temperature box) of the refrigerator and freeze them thoroughly, and then move them into the freezer. After a few days, the pages will be as dry as usual without warping or deformation.