I have quite a few old military 308 brass that needs to be resized using a small based die.

Is it possible to remove the decaping pin from the die lub the outside of the case and resize? Then remove the lub on the outside of the case. What if some lube gets inside the case from the neck sizer? Can a Q-tip clean it out? Would it affect powder when loading? I can't find any new primers anywhere. Powder is showing up as well as bullets. I have about 100-150 of these that need to be resized.

I have done exactly this, resizing primed 30-06 brass to 35 Whelen. Depending on what brand of die you have, the decapping pin ay be part of the expander ball, so it is not removable. (I have many Lee dies that are set up like this). Other die sets, the decapping pin in a separate piece that can be removed (I have an RCBS set like this). I use a lube that claims to not affect powder, so I don't worry about removing lube from the inside of case. If you wish to remove the lube from the outside, I sometimes dry tumble the completed cartridges. You do not want to dry tumble just a primed case, as the media can clog up the flash hole and you would never know it until the cartridge didn't go "bang". Of course, some say that you should not tumble complete cartridges, but I will leave you to do your own research and make decisions on that.

I have an RCBS with removable decapping pin. I will check the various types of lube. Right now I am using paste lube, but I will check. I too have made 35 Whelen from 30-06 brass, but not with primed brass.

Glad to know it can work. Thanks.

No problem. Hornady One-shot spray lube is what sits on my bench when I'm trying not to contaminate powders or primers.