How to clean stainless steel insulated cups?

How to clean stainless steel insulated cups?
【 How to clean stainless steel insulated cups 】 1. Method 1: First, clean the inside and outside of the insulated cup with clean water, and then use a toothbrush dipped in a little edible salt to carefully brush and grind every part of the cup. You can find that after daily cleaning, the tea stains and other attachments inside the cup immediately disappear. Then, clean the inside and outside of the insulated cup again with clean water.
2. Method 2: Dilute with kitchen specific bleach and water, then pour into a insulated cup. Shake several times and soak overnight. Rinse with clean water the next day, and the tea stains will miraculously disappear.
3. Method 3: First wet the cup with water, then squeeze a little toothpaste into the insulated cup, soak it for a while, and then use a clean cloth to rotate and wipe it clean to remove tea stains.