Read the following text and answer the question!

    If you've ever been naïve enough to stick a ballpoint pen in your pocket for safe keeping, you probably learned there's nothing safe about ink exploding all over your clothes. Don't give up on those jeans yet —they may not be beyond repair. However, not all ink types are the same, so the treatment varies accordingly.

    If you get ballpoint pen ink on a piece of clothing, put a paper towel under the stain. Then, apply some standard rubbing alcohol to the affected area. Larger stains may need to soak for up to 15 minutes. Blot/sponge at the stain with a clean cloth until you notice that ink is no longer being transferred. Rinse, apply a pre-treatment (if you have one), and wash as usual in hot water.

    Ink from a felt-tip pen is often a little tougher, but still totally possible to remove. Experts recommend that the stain be rinsed thoroughly in cold water. Next, soak the garment in hot water treated with some liquid laundry detergent. Add a little ammonia as well, if you have it. Make sure it's all mixed up, add the item and rub the stain gently. Allow it to soak for 30 to 60 minutes, or even overnight if the stain really doesn't want to go away. Once it appears to be gone, rub in a little more detergent, then launder.

(Adopted from: https://home.howstuffworks.com/home-improvement/household-hints-tips/cleaning-organizing/10-quick-tips-for-removing-stains-from-clothing8.htm (April 21, 2019))

When ink stain from a felt-tip pen seems to disappear, we should ____.