Can message folder be emptied completely?

Hi fellows,

recently i tried to "master reset" my P800. Well it didn't agree with
me! The first time i tried some applications have not been erased! I tried
a second time and it worked.
After that tried to restore my backup and "crazy" things happened! The
message folder appeared to be larger than before! Then i deleted all (and i
mean ALL) the messages but it seemed that the phone had a differrent
opinion! The folder still occupied 1.7MB (even after it has been emptied)!
Any opinions ?

Thanks a lot.

Daniel Gogos