Disclaimer: I am the current author of the "rawhide"rawhide ("rh"rh) program that is used in this answer (see raf dot org slash rawhidehttps://github.com/raforg/rawhide):
rh -UUU '"*/rules/*.pdf".path' The '"*/rules/*.pdf".path''"*/rules/*.pdf".path' argument searches for pdf files inside/under directories named "rules".
The -UUU-UUU argument deletesunlinks/removesdeletes/unlinksremoves the matching files.