The latter was a very old instrument; it had sockets graded to fit Nipples of various sizes.
"Reminiscences of a South African Pioneer"
W. C. Scully
Finally, mothers can be taught at home how to cleanse the bottles, the Nipples, all milk receptacles, and all things in rooms where milk is kept.
"Civics and Health"
William H. Allen
Later, the bottles and Nipples should be carefully washed in hot, soapy water, then rinsed in clear, hot water.
"Ontario Teachers' Manuals: Household Management"
Ministry of Education