I'm worried about my AK. It's been a long time since I've seen her or talked to her. I won't be home for another 10 months. I fired Yugoslavian corrosive ammo before I left two months ago, and let it sit for a day without cleaning it or running water through it. A poor decision. Sharon, I will never do that to you again! There was some rust in the gas tube before I left. I used a cordless drill, cleaning rod, and a 12-gauge brush to clean out the inside of the tube by assembling the brush on the rod and then spinning it around inside the gas tube with the drill. That took care of most of the rust. I hosed it down and oiled it up good afterward. But, I'm worried about it re-rusting while I'm gone. Will my gas tube be rusted to pieces when I get home almost a year from now? Will there be holes in it? Can I chrome-line my gas tube myself, somehow? Where can I buy a new gas tube? I saw one once for $50. Dang, it was just a few years ago when you could buy a whole parts kit for only $100. I miss those days...
I'm not clear on whether you're still home or already gone.
If you're gone, there's of course nothing you can do now.
If you're home you can make sure it stays in great shape.
One is to thoroughly clean the rifle with hot soapy water. You need to thoroughly flush out the corrosive residue wherever it may have come in contact with the rifle, which would include the bore and chamber, any muzzle attachment, gas block, gas tube, gas piston and bolt carrier, bolt, and around the chamber area of the receiver.
In other words, wherever you think the fumes contacted.
After the water flush, dry it, then clean the rifle with a bore solvent including the bore and chamber, gas block, gas piston, bolt face, gas tube, and muzzle attachment.
Once clean, coat everything with a good rust resisting lube like CLP Breakfree. I use a clean, soft toothbrush with a few drops of CLP on it to "scrub" all surfaces. This leaves a thin coat of CLP which is one of the top rust preventing lubes.
Apply some inside the bore and chamber, gas tube, gas block, etc, any where you can.
If you live in a humid area, or have to store it in a damp area like a basement or closet, you can absolutely insure no rust by buying one of the VPC bags and sealing the rifle in the bag.
The bag gives off a vapor that drives out moisture and surrounds the metal with a vapor that totally prevents any rust for at least 10 years or more.
Properly prepped and sealed in one of these bags and you'll have no problems at all with any degradation of the rifle.
Best of all, when you get back, all you have to do is run a patch down the bore to remove the thin layer of CLP and you can go shooting immediately with no nasty degreasing to get grease off.
So sorry that happened. Your best bet is not to ever fire ammo that is corrosive in nature cuz you can be sure of corrosion taking place.