You could try glogarchive, it's for archiving messages and call log. (i don't know if you can restore the messages afterwards, but you will be able to read them via this archive application anyway)

There are less invasive solutions (which don't require database removal), but taking into consideration you haven't found them and you are not a "pro", I think you should go with this one, as the other two solutions can bring more harm than good if you do something wrong.