How to clean a white shirt?

My mother taught me to wash white clothes like this since I was a child:

Soak the clothes completely, then pour out the excess water and start soaping (I usually use whitening soap). When you're done, rub them properly and let them foam. Don't rinse, put 15 minutes and rub it again, and it will be very white ~

As for blue ink, it does have a whiter effect, not really whiter, but whiter. (Of course, it is only used when the white color begins to turn yellow, not when it is not as white as before because of long-term washing ...) Note [Don't use too much], just use one or two drops in the cauldron, and be sure to stir it evenly.

I love wearing white clothes. I have been washing white clothes like this for so many years, and I have never used any bleach or anything. I always feel that it is not safe to use those things ... Besides, I can clean them in the simplest way, so why not? )