Old NSEs sitting in the queue

I have this issue with NSEs just sitting in the Queue on the NS. Right now there are over 100 that are many many days old. New events that come in are being processed but it just seems like for every day I get 10-15 that just decide to sit in the queue forevery. I'm not sure if there is an error in processing them or the event processor is just skipping them for some reason.

Does anyone know if I can manually trigger processing of an NSE to see if there is an error related to it or some other way to troubleshoot this?

Thanks for any assistance.