[galaxy-user] reducing size on disk to comply with quotas

Hi, I am currently using 636gb of storage and would like to reduce it. I have deleted (from disk) most of the datasets in my history. All I've kept are the Bam files which are around 2.7gb each . Unfortunately, the "size on Disk" reads 448.5gb in my saved histories window. It is my understanding that permanently deleted datasets are not considered in quotas. Also, I don't have any copies of these datasets. Where is the 448.5gb of data coming from and how can I get rid of the phantom gb's while keeping the bam files? Thanks, Patrick