Regarding copper tub and the jam pot someone asked about. Catsup and
lemon are both indeed to get through the grime. However, if you would
like to save the old, “used” looking patina, you might try something like
Murphys Oil Soap or a similar detergent with very warm water… Use the
soap on a piece of cheesecloth or an old terry towel and add lots of elbow
grease. This should allow you to keep the “antique” look in tact.
Trying a little bit of catsup, lemon, and soap in spots on the bottom of
the tub will give you an idea of the different colors produced by each
cleaner.
Hope this is helpful.
Joyce in Colorado