Abstract: In a friction spinning process, a method is provided for preventing build up of dust and fly etc. inside a friction spinning machine (1) which method comprises the steps of introducing into the machine a flow of filtered air at a pressure just sufficient to substantially prevent the ingress of unfiltered air during spinning. The invention also provides apparatus for performing the method described, which apparatus comprises filter means (19), pressurizing means (20), ducting (22, 23) adapted to permit the outflow of clean pressurized air into the inside of the machine (1) adjacent the or each spinning head (3) at a pressure sufficient to substantially prevent the ingress of unfiltered air during spinning.