OK so I was rooting around in my elderly Aunts garage and I came across a couple of the old style red metal jerry cans with the wide mouth. OK here is the problem, the cans have been empty and within  200 yrds of the Pacific Ocean for who knows how long and they are rusted in the inside.  When I shake the cans your can hear the rust and debris inside, is there anyway to salvage these? Or have I just hauled them home for no apparent reason.. Thanks for your support

Look in all the threads on gas cans in the gear section and this section.  There are some repair kits linked in more than one thread.

You may only need to clean the rust out and put the cans to use.

If you got the cans for little and have little shipping invested then you will at least get some learning out of the cans.

If they aren't rusted through, you can get some of that gas tank conditioner they sell for motorcycles.  Haven't priced it, though, so you may not be saving anything over new cans.

Which reminds me, I've got a bike tank that needs a treatment, so I'd probably better figure out how much it costs

What I do with cans as you describe is put a few handfuls or more of course dry sand or small gravel and shake them around a bit to loosen the worst of the rust and scale.  Then I dump them out and wait for the dust to clear before inspecting them with a flashlight. If they look relatively ok inside at this point I will put a quart of kerosene or diesel fuel in to check for leaks.  If they don't leek I will use them as is.  If they still looked rusty I will put a gallon of muriatic  acid and few gallons of water inside and slosh them around to completely dissolve the rust. Pore out the solution and rinse with water completely. immediately pour a  bottle of heat or similar product inside to absorb the remaining water and rinse with a quart of kerosene or diesel.  Check for leaks.  If they are  not leaking then they should be good to go for kerosene or diesel storage.  If you want to store gas in them it may be a good idea to line them with fuel tank liner.  small leaks can also be fixed with the fuel can liner.

Thanks for your help on that.. So I am assuming that the fuel can liner is "paint like". and it will coat the inside of the cans? I am going to give them the sand treatment and see of that helps to break some of the flakeing loose.  I was going to use them to store Diesel as part of my Bug out package.. With an extra 10 gals of Diesel will give me an 800+ mile range on the big dodge.. Thanks again..

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Evaporust.  Then, when clean, use a gas tank coating product to prevent future rust.

I don't bother lining cans that don't leak for diesel or kerosene storage.  I've never had on rust that was used for such.

I coated the inside of a 2.5 gallon Jerry can this weekend.  It had a bunch of rust flakes in it, so I put some gravel in it with some gasoline, shook it around a bunch, and poured it out.  Then I put some vinegar in there (I heard it dissolves rust?) and left it for a while, turning occasionally.  Finally I rinsed that out with fresh water, let air-dry.  Then it was ready for the fuel can liner.

I read some reviews on Kreem, Red-Kote, and another liner (I forgot the name), and was disappointed in what I read about Kreem.  I got 1 quart of Red-Kote from an O'Reilly's auto parts store for $22.95 + tax.  You pour the whole quart of Red-Kote in, close the lid, and slowly turn the can so the entire interior is coated.  Then pour the excess back into the original quart container for future use.  Let the can air-dry, laying it on its side, and turning every few hours to minimize "puddling".  Let it dry for 24 hours or so and you should be good to go.

I also have a 5 gallon jerry can with a very small hole in the bottom I am trying to figure out how to patch.  Any ideas?  I am not a welder, nor do I have access to a welder.  The hole is about the size of a ball-point pen tube diameter.  If I can get it patched, it will get Red-Koted as well.

How do you want it to look when you are done?

I've use some epoxy fuel tank repair that I got from wallyworld auto/boat department with good results.  You could tell that I had pressed the putty to the tank, but cosmetics did not matter on that repair.  You might get a nice get a good external finish with a tool like a putty knife.

Other things that I can think of are pop rivet, or welding.

One guy I know recommended a screw, a washer, and JB Weld (on the inside of the washer, screwed into the gas can).  I'm thinking that would look tackier than I am interested in, but I was wondering if JB Weld by itself would work.  The hole is at the bottom of the can, so I could push some through the hole from the outside, then smash it down on the inside with a dowel or something I could stick through the spout.  I just don't know if it would bond to the actual metal surfaces inside and out well?  Since the hole/repair is on the bottom of the tank, I'd need a fix that can withstand the abrasion it will see from a full can resting on it, and while not being abused, not necessarily being treated gingerly, either.

The gas tank sealer kits that Eastwood makes are well-regarded, but they're not cheap...You could easily end up spending more on the sealer than you paid for your gas can!

The epoxy that I used felt tough when cured YMMV.

With the location that you describe and the skills that I have gotten since then I would do a flush rivet.  Make nice with someone that fixes airplanes, and they might be able to help you.

Try a closed end pop rivet.

Soldering is a good skill to acquire and cheap to buy tools for.  Brazing isn't much harder or more expensive, and opens up a world of repair rather than replace opportunities.

Another way to check for leaks is to put just a few ounces of gasoline in them, seal the filler hole, and leave them in the hot sun for an hour or so. The sun will heat the can, making it expand; if it holds the (very minor) pressure that builds up, then the can is GTG.