After downloading many small files if you start to uncheck and delete some of those files from tixati there will be a crust file left that is data maybe used in other files (as far as i understand) which makes sense for 1-2 files but after many there will be left a large number of crust files that are not used anymore by other files and take 3-20mb per file of disk space.(in some cases images will retain all data as a crust file)
For now i am using this workaround: https://forum.tixati.com/support/5684  
but deleting all crust files will make it necessary for some files to be partially re-downloaded to be seedable and it takes time

Can you please add a "Delete unused crust files" button or something more elegant