Help with Stock Prep Help Please

[Jungle George]

This is the first time I have ever looked to sand down and re finish a stock and I am not sure on what is best at this point. The previous owner of the gun must have dipped the stock in a vat of varnish judging by the quantity of the stuff that I have removed, this same person also spray painted all the metal work with gloss paint but that is a job for another day. Anyway, I have removed most of the varnish and am left with some stubborn spots on the gun where I assume the varnish has just soaked in a little deeper, the stained spots can be seen on the pic's. Is there any advice anyone can give which would make removal of these stained patches easier or is it just a case of good old fashioned elbow grease and lots of sanding required.
http://s1079.photobucket.com/user/ge...tml?sort=3&o=2
http://s1079.photobucket.com/user/ge...tml?sort=3&o=5