While this isn't an application, going through terminal like
Dresevski said is a good idea as long as you are comfortable doing so.
Now there are numerous ways to delete items in the Trash through terminal. Though since you have nearly 5000 undeletable items, this may be a permissions problem with your Trash folder. So best bet would probably be to delete the whole Trash folder and have the OS recreate a new one which should have correct permissions from the get go.
Now assuming these files in the trash are from your harddrive and not an external one you have plugged in (as that trash folder would be located somewhere else...) open up terminal and type..
Make sure you type it exactly, or even copy/paste it into terminal. If even a character is off as always there could be dire consequences. You will then be asked to input your password, and then since you have 5000 items, this deletion will take a few moments. Now assuming this was successful and you received no errors, you no longer have a Trash folder, so if you try to delete anything you will get a message saying it will permanently be deleted.
To fix this, now restart your computer, a new Trash folder will be generated with correct permissions and everything should be working as it should be.