How to clear old deferred printing files

In our deferred printing directory, there are about 7500 files, and the list of deferred documents to print goes back to 2010. 

I've been on the job 3 weeks. 

Is there any way to get rid of all those print jobs? I tried to print to a Nul printer, but it told me that the files could not be found,  and is unable to print. 

Thank you in advance.