The only problem with this is the same with all of the autosave features in MapTool; they do not have a setting that says only use XXX MB of space before freeing. So you would need to know that the files exist and manually delete them.
Yep, this is a problem. I would like to have a comprehensive "pruning" function in MT but I'm not sure how that would work. We don't want to prune the assetcache of assets that are actually being used. On Un*x-like systems we can use the access time of the file (known as the "atime") to determine if the file has been accessed recently. Perhaps sorting by the atime and then deleting the oldest ones until the remaining space hits a user-specific threshold would be good enough?
I've had this kicking around in the back of my mind for quite some time and need to figure out the specifics for 1.4/2.0.
One time I had over 20 gigs of files in my assetcache.
Not necessarily a bad thing. If you delete all that, then you simply need to download it again when it's used in the future. Much better to leave it there unless you actually need the space for something else...