take a nice stiff metal bristle boar brush (not the one that comes in the sks cleaning kit) it isnt stiff enough bristile wise for what you need to remove, ie rust not just gun powder foul. Run it up and down the barrel for a good 5 minuties from the muzzle and the chamber,
Than run patches through the boar wet with WINDEX untill it comes clean,
than run dry patches through the board untill they come out dry than run a nice wet patch of gun oil through the boar a few times and let that sit for a few hours letting your poor barrel soak up some much needed lubrecant.
After sitting run patches through boar until dry again,
Clean all your receiver parts use a wire scrub brush to remove rust if you have any showing clean parts with windex and and apply a nice coat of gun oil accordingly