This essay makes a contribution to our current understanding of how solfeggi were used in the Neapolitan conservatories in the late eighteenth century. To this end, I investigate how this repertoire was used and applied, both in practice and in written counterpoint. Through documentary evidence derived from student counterpoint notebooks, the article reveals how themes in solfeggi by well-known masters were reused and adapted in lessons of written counterpoint. These findings suggest that vocal repertoires that were sung in these pedagogical milieus were borrowed by teachers and students through techniques of transformation and adaptation in order to be reused in new compositions.