I don't want attachments might be randomly removed if they are still useful.
For example we have attached some small Bluecharts g2 or some islands Topo Maps.
Some files cant be found in the net anymore after some months.
Useless threads go to trash and big attachs usually are deleted; from time to time a check in Admin CP is made to remove useless files.
A script IMHO cant substitute this kind of job unfortunately.