 Rosenberger was often booted out of synagogues and assembly halls with derision by the public who did not believe him to be genuine.Rosenberger introduced a method of sample testing, which enabled one to certify a garment to be free of having shatnes, without thoroughly testing the garment.This included the ability to use unskilled persons across the United States of America who were coined with the term "sample testers", as they were able to take samples and send them to Rosenberger to verify them as being free of shatnez even though they were relatively untrained.