I found this rust removing product online.
www.rusteco.com
You just dump the liquid into your tank and let it sit.... done. It won't eat the paint or anything, just rust. They also have gel version, where you slap the gel onto wherever you need it, even on painted surface. It sounds pretty cool if you ask me. Anyone have any experience with this product? or is it just another too-good-to-be-true scam? I'm really thinking about buying this..

I used that last fall. I thought it was expensive but went ahead with it anyways.  I have to say it worked pretty darn good. I let it sit for a week and when I dumped it out the tank lookeds great.Ccouple things  I will mention.  The top of the tank around the filler neck (I have a 94) did not get good contact with the liquid because it is hard to get it to fill up to that point. I may consider doing it again and just flipping it upside down but  we will see. Second, once i was rinsing it with hot water, the flash rust starts quick. I personally don t care about it but some people might. The faster you can get it dry and oiled the better. alcohol probably a good option that i never used. If I had to do it again I might try evaporust first just from a cost standpoint. In the end my tank is clean and my paint is still perfect.

Tank Capacity 5 gallons $125

You pay me that much $ and I'll POR15 coat the bloody thing and give you a 10-20 back after shipping it back.

Anything that says it treats rust, but has a flash rust warning = garbage.

You can do better with a 20 ft length of puppy dog chain. Hold 1 end - prolly bolt it in the cap bolts, and toss the rest in, and shake like a maniac. Then toss it and slosh with gas and toss it. There I saved you 100 bucks atleast. Oh yea, watch for flash rust and fill with oil and or gas.

Steps to real rust proofing is simple, but need adhered to 100%.

Clean, Derust etc - I do it with acid - muriatic or the POR15 acid, and more rust = muriatic and POR15 acid after that, light = POR15 acid.
Then dry and do not let it rust. Hot water and dry it as soon as you possibly can. Towels cut to shreds, bedsheets etc etc etc ... stuff em in, shake and dry ... hot air, oven, dessicator, surface of the sun ... anything.
Then drop in the right amount of POR 15 - 6-8 oz for a GS size tank, and slosh till you see no wet POR15. Then toss in in a car parked in the sun and let it styme for a few days. That is it. I will do these and some optional mods for 75-100 bucks - POR15 etc etc included.

Cool.
Buddha.

Thanks for sharing!
Here's my question... "once i was rinsing it with hot water, the flash rust starts quick."
I thought all you have to do is to blow it dry with compress air... It said no rinse on the website. Maybe I read it wrong.
Maybe you think acid is better for the tank but for the rest of us who are not as skillful as you are   , the safer the better. Especially I'm not in a hurry to get it fix. If it is totally fool-proof, I can wait a couple days.
Anyway my tank is in good shape on the inside, what I really want to do is slap that gel right on the outside of the tank and the frame to get rid of the surface rust before it screw up the paint and the frame.
Atleast now I know it actually works, I guess i'll drop that $70 to give the gel a try! I'll keep you guys posted! 

Light rust = POR15's marine clean, and metal ready. That thing yea its an acid, much like this is an acid, but its not even as strong as lemon juice.
I would try POR15 before dropping 70 bones on this crap.
POR15 - really seriously good stuff.
Cool.
Buddha.