This great article from YIVO on European Jewry and health has this fantastic image from the 1920s from a spa:

Sara Berland and her daughter, Felicja, from Chełm, visiting Krynica, a town in Poland famous for its spa, 1920s. It was traditional for visitors to a spa to carry around their own cups, which they used for drinking the mineral waters distinctive to each spa. (YIVO)