I found a really old juice pitcher at a thrift store (not GW,for once). It looks 30's or 40's to me. Even has the top. However, when I got it home, I saw lime deposits or something like that inside the pitcher. This led me to many hours of research on ridding glass of lime/mineral deposits. I tried alka seltzer (didn't work), then vinegar and water (didn't work). One book suggested boiling the leaves of a rhubarb - only problem is, the fumes (and the liquid) are poisonous. I had to draw the line there - not willing to try poison. So I decided to use it as a flower vase. It looks pretty good with flowers in it.
My mother used to use denture cleaning tablets to clean vases and such. Fill the pitcher with ater adn drop ina couple of tablets. Should be safe enough to use. People use it and then put their dentures back in. Or you could try the baking soda and vinegar trick.
Jeannie