Emil was involved in many business ventures in Rybnik, as the advertisements and notices below illustrate. Among them he had a cloth and clothing shop in Rybnik, selling to both retail and trade customers. In part this was probably an outlet for fabric that came from the family-owned dying and print works.

In 1911 Emil sold the clothing business, which it is claimed had been in the family for over a century, to a Mr. Leschcziner. In December 1924 Margareta Leschziner geb. Friedlaender was added to the business register as an authorised signatory for the business known as "Emil Prager's Nachfolger [sucessor]". A Salo Priester must have also had an interest in the business, because in April 1927 his widow, Olga, was appointed in his place. In September 1928 Marta Leschziner became the owner. The business continued to trade until 1941; an advertisement in 1940 names Wilh. Mateyka, but the notice of its closure names the owner as Maksymilian Leschcziner.

During the Second World War Emil and Minna were among many refugees registered at 53 Belsize Park Gardens in London.