Redmine

We are using Redmine as an internal web portal where we upload and store large files. Currently our web server has a 4GB /tmp directory, and when we uploaded two 2.2GB files the /tmp directory went to 100% and the second upload failed. It looks like Redmine is not going back and deleting the temporary files it is putting there during the uploads. Is this a known issue and if so is there a way to get around it other than expanding our /tmp directory?

Thanks