Toothpaste would make a decent coarse pre-polish but it leaves scratches. Plastic toothbrush will not scratch it is much softer than gold or silver. Toothpaste is harder than gold that is why it scratches. Scratching is a form of polishing. I use diamond to polish gems which is actually scratching. I gonna contact
Kevin Jewelers reviews to get some recommendations. The problem with toothpaste is it is too coarse and does not leave a good high polish. If you like the look with toothpaste go ahead and use it. But there are better ways ton get a high polish.