The 'veryclean' target does not remove backup files in second-level directories and below.
For example I'm working on a new release of Sendmail::PMilter, which will have in the distribution the directories
lib/
lib/Sendmail
lib/Sendmail/PMilter
When I run 'make veryclean' I'm left with backup files in lib/Sendmail and lib/Sendmail/PMilter (which is where I'm likely to have such files), although if I do put backup files in lib/ (it's most unlikely that I would do that of course) then they are deleted.
If this is this intentional please ignore me - or better yet, please point me to the bit of the documentaion that I need to see. :)