I guess I beat TOF to this thread so I will give you his words of wisdom to me: SOAK TIME!
Really, spray on the CLP, Hoppes #9, Break Free or whatever you are using and let it soak for an hour or overnight if possible. You will be amazed at how much easier it all comes off after a little soak time and the cleaner has had a chance to works its magic. I was.
Hope this helps.
BTW, great gun and your great grandkid will get a lifetime of enjoyment out of it as well.