PHP：清除cron临时文件的好脚本？

I have a temporary folder generated by my business application and wish for the documents within to be only available for around 30 minutes. I was tempted to build an index to keep track of when each file was created but that would be a little silly for just temporary files, they are not of too much importance but I would like them to removed according to the time they were last modified.I have a temporary folder generated by my busin