I just bought a old house and I love it! It has alot of the old touches love it love it. But the sink has stains. I didn't want to use bleach but on of my friends that was helping me move in poured some bleach in it and it didn't get rid of it either. I remember seeing something about baking soda but I can't remember what it was mixed with or how you did it. SOOO. if any one knows how to get rid of it please let me know..
Also along the same lines as Barkeepers Friend is one called Zud. I bought mine at WalMart. When we bought the house we're in now, I had to figure out a way to get the stains out of my porcelain tub (lots of water stains and just old age) because I wanted to keep it (nice and long!). Zud cleaned it up like it was brand-new.
I've had great luck using a pumice stone. You can get the little ones at the drugstore, but I did find a huge one in the home cleaning aisle at Walmart. We get unbelievable rust rings here and this takes care of it.
I used to teach school in a super old (over 100 years old) school house...I tried everything to get the sink/fountain in our classroom clean...the winner was Ajax with ALOT of elbow grease...I mean I scrubbed that sink for 30 minutes or more! Good luck Kate