How do I get the rust out of the gas filler neck?

[sixpack_sid]

I am restoring a 68 Charger and there is rust inside the gas filler neck. The neck seems pretty solid, just one rough spot at the top. Anyone know what would be the best way to remove the rust? Can I dip it in anything, or use rust remover, sandblast it? Any ideas?

[tan top]

i had a similar prob !!  i was going  blasted it !!  i doubt it would of removed all the rust specks as it was all down near the bottom where it was divided into two !

   so what i done  bought  Por 50  gas tank repair ... just follow instructions    marine clean & rust remover  ..really does work    then seal it in with the sealer 
worked for me !