Emptying trash is one of the most annoying thing I do in my WordPress blog since this is one of the most forgotten directory in my website. If the trash is left forgotten, you will end up with a heap of unnecessary files that can hog up your system or slow down your site. What if you can empty trash in a frequent basis without having to do anything but set up this feature once? Before you proceed make sure that you won’t be getting back to your deleted files and you know what you are actually doing.
Read full guide here: http://www.wprecipes.com/how-to-automatically-empty-trash-on-a-daily-basis