I must admit, I don't have a 3.5" head
cleaner; and dust ingress could be a
If by that you're refering to one of those cleaning disks, my only
comment is 'Good!'....
IMHO the only way to clean the heads is to remove the cover from the
drive and to clean them carefully with a cotton bud soaked in propan-2-ol
(isopropyl alcohol, etc).
-tony