1. Use toothpaste: apply a proper amount of toothpaste to the scratches on the porcelain bowl, and then gently wipe with a wet cloth until the scratches disappear. Finally, rinse with clean water.

2. Use baking soda: clean the scratch first, then mix baking soda and water evenly at the ratio of 1:2, smear it on the scratch, let it stand for a while, and then wipe it clean with a wet cloth.

3. Use vinegar: clean the scratches first, then pour an appropriate amount of white vinegar on the soft rag, and then gently wipe the scratches.

I hope the above methods can help you solve the scratch problem of white porcelain bowl.