Delete ._ Files from Network Drive

I've seen a number of discussions regarding this, but haven't found anything that has a straight forward, idiot proof method. I'm no Terminal wizard so all these lines of commands with no explanation mean nothing to me, I'm hoping someone can explain a relatively simple (or copy and paste) command I can use!

I have hard drive attached to my router working as a NAS drive, which is my main source for a media library (XBMC) running on a Raspberry Pi. I recently noticed that whenever I copied a file from my Macbook Pro onto that hard drive, XBMC would show two files that would appear exactly the same but one of them wouldn't play. When deleting these files I noticed that the "dead" files always started with a "._" before the normal file name.

My dad can see all these files and just delete them manually, but we have a massive media library and it's a total pain to sift through and do that as it'll take forever!

Is there a way, without using third party software that costs any money, to make these files visible within Finder so I can delete them from the network drive? They aren't a problem on my Macbook Pro so that's fine, I just want them off the network drive!

Any suggestions would be great, thanks 🙂