first post, need info on postgres + storing objects (getting rid of them mainly)

hi,

if this is the wrong place to post, please let me know.

I am trying to fix a mess on a system running a postgresql database (7.1 I
think)
java objects where stored on this server but it seems to me that when the
rows
holding the OID's of these objcets are deleted, or the tables holding the
multiple
rows is dropped, the attached objects aren't removed themselves.

(I have double checked this assumptionof mine just now)
for each OID with number yyyyyyyyyyy there is a file in the datadir named
xinxyyyyyyyyyyy (header?) and a (value?) file of xinvyyyyyyyyyyy

both files are not removed after dropping the rows linking to these files.
am I doing something wrong here, or is this a 'feature'? Does anyone have
similar problems?

I tried the vacuum function which only sizes down some system tables but
leaves
the object files untouched. Is there another function I should be looking
into?

for info: I have 400.000 files in the datadir by now and still growing.
------------
and now for my question, the above is just a cry for help and you can ignore
it unless
you actually have 'the' answer for me. (in which case you have my gratitude)

Q: is it possible to delete files from the database directory (xinx11111 and
xinv11111 files)
without the rest of the system becoming unstable?
(ofcourse I mean only those files that are not referenced by the database at
that point)
Are the files on disk referenced from any system tables and if so will the
disappearing of
these files cause serious grief for me and our customer?

I really hope you can help me.
regards,
joris hilhorst