Removing user-defined types & functions

hi!

I was playing with creating my own types and C-functions and have
notised that after one of my own types was removed functions that use it
became unexistent(i can't call them any more) . But still there are
all tuples in pr_proc that describes all that functions. So, my question
is: can I (or should I ) remove manually from pg_proc(and may be , some
other places) any mention about functions that haven't been deleted by
" drop function " operator but already unavailable 'cause type they use as
an argument type have been deleted.

Thanks.

Aleksey.