Lay the Japanese woodblock print flat on a surface over a white towel. Put on your latex gloves and pour 1 part distilled water and 1 part hydrogen peroxide into a bowl. Mix the contents gently until blended.
Add 4 tbsp. of the mixture into a clean metal dish. Take a cotton ball and dip it into the solution. Blot the cotton ball on a towel so that it is damp, not saturated by the solution.
Gently blot the stain on the border of the print, never rub it. Do this until the area is slightly damp. Throw away the cotton ball and dip a new one in the metal dish --- never put a used cotton ball back in the metal dish. Repeat on any other stains on the border.
Rinse and dry the metal dish after all stains have been blotted. Pour distilled water into the clean metal dish. Using a new cotton ball, repeat the process from the previous step to rinse away the hydrogen peroxide.
Place the damp print in between two paper towels, then insert all three items into the middle pages of a heavy book, such as a large dictionary, and close it. Leave it for four to six hours so the paper towels absorb any moisture.