Alkalies
Remove alkali spots at once; they may destroy not only the color but the material as well. First sponge or rinse the spot thoroughly with cold water. This generally is sufficient for mild alkalies such as washing soda and weak ammonia water. But to be on the safe side and to help restore color, apply an acid—this stops the action of the alkali. Then rinse or sponge the spot thoroughly with water. Use any of the following mild acids:
Lemon juice.—Squeeze the juice on the stain, and allow it to remain until the juice loses its bright yellow color. Sponge or rinse well with water.
Vinegar.—Sponge with vinegar; then rinse in cold water.
Acetic acid.—Apply a few drops of a 10-percent solution of acetic acid with a medicine dropper or a glass rod and remove the excess by rinsing or sponging with water.