Method 2: Squeeze fresh lemon juice, drop it on the rust, rub it by hand until the rust is removed, and then rinse it with clear water.
Method 3: Wet the contaminated area with 10% citric acid solution or 10% oxalic acid solution, then soak it in concentrated brine and rinse it off the next day.
Method 4: vinegar rust removal method: soak the dirty place with boiling water first, then rub it repeatedly with vinegar until the rust is eliminated, and then rinse it with boiling water after a few minutes.
Method 5: Rust removal with yogurt: first soak the rust with water, then coat it with yogurt and soap, slowly knead until the rust is removed, and then rinse it with clear water.
Extended data
Deal with pen marks on clothes
First, pour alcohol on the scratches of the fountain pen on the clothes and cover each scratch evenly with alcohol. Alcohol should be medical alcohol with a concentration of not less than 75%. Turn the alcohol side of the clothes up, and try not to touch other sides of the clothes, otherwise the marking color of the pen or ballpoint pen may be dyed to other parts of the clothes.
Prepare more than half a basin of water with an ordinary washbasin, and then pour two bottles of bleach into clean water. Be sure to fill two bottles. Take it and stir it, and add a little washing powder. You can control this amount by yourself.
After that, stir it a little to make the washing powder completely soluble in water. Ok, now soak the clothes completely in water for 20 minutes. Time's up, laundry, no trace!
If there are traces of ballpoint pen and the traces are heavy, if there are traces after using the above method, finally wipe them gently with toothpaste and soap, and then rinse them with clear water. (But boiling water is forbidden! )
There is another way to solve the problem that clothes are stained by ballpoint pens: don't rush into the water, but wash the dirty parts with gasoline first and then wash them.