You could use a scheduled process trigger to periodically call a JSS script that iterates through a folder-tree deleting any files that are older than 14 days.
var maxAgeInDays = 14;
var baseFolder = "/Home";
// Deletes all files in the given folder (and all its sub-folders)
// that are older than maxAgeDays
function deleteOldFiles(folder) {
console.debug("Deleting old files from " + folder.fullPath);
folder.getFiles().forEach(function (f) {
console.debug("Found file " + f.fullPath);
if (f.name.indexOf(".zip.folder") >= 0)
return;
if (f.isFolder) {
deleteOldFiles(f);
f.removeFolder();
} else {
var now = new Date();
var msPerDay = 1000*60*60*24;
var ageInDays = (now.getTime() - f.modifiedTime.getTime()) / msPerDay;
if (ageInDays > maxAgeInDays) {
console.debug("Deleting " + f.fullPath);
f.removeFile();
}
}
});
}
// Call removeOldFiles on the base folder
deleteOldFiles(system.getFile(baseFolder));