Here is a simple tactics to automatically or inexorably empty your trash(recycle bin) on daily, weekly and monthly basis
Steps to empty your trash in wordpress
Locate your wp-config.php file of your wordpress blog which can be found in the root folder of your wordpress blog throgh your adminPanel File Manager.
Edit the file and include this code at the last line
Replace 1 in the code with the number of days you want it to always empty the trash. If you leave it as one it will be emptied everyday