I just found out the other day, that placing something on the bottom of the sink is a good way of protecting it against scratches. When it comes to scouring big pots, it can be difficult to keep the pot steady. The movement will scratch the sink and make it look bad.
I suggest putting some hosiery at the bottom of the sink, and then placing the pot on there. You obviously can use other materials, too.
Thank you for reading!