They had aw46 hyd oil.   Would these be ok for fuel storage like gas or kerosene. If so what is best way to clean them out  thanks.

Here's the little FAQ I've put together on my gasoline storage.  At the end there's a bit on cleaning oil drums.

I've put together a sort of FAQ out of answers I've given on this
topic.  It's not complete, but nothing is.

(storing gas:  winter or summer gasoline?)
I store winter gas for a couple of reasons:

First, it is usually cheaper as the summer driving demand slows and refineries
buy more heavy crude (to make heating oil) which usually drops the price of light sweet
crude.

Second, northern states increase the percentage of lighter fractions (butane mostly)
to allow for easier starting in the winter. In a sealed container (I store in sealed 55
gallon drums) this creates a positive pressure in the drum which keeps out oxygen
and water. Don't seal them without a pressure relief valve if you can't keep them
in a deeply shaded location, I've had drums look like carbonated soda when I open
them for the first time in August, it's also a good test of the integrity of the drum,
I tend to notice minute leaks when the pressure rises like that.

The second reason there doesn't apply if you live in a state that doesn't regularly
drop below freezing in the winter.


(Storing gas.  55 gallon drums, plastic or steel?)

First of all, there's no one "plastic". There are lots and lots of different
types of plastics and some are resistant to almost all solvents and some
will disintegrate if you look at them wrong. MOST 55 gallons plastic drums
are made of HDPE and will hold gasoline and diesel just fine. I don't speak from
anecdotal experience, I've been storing gasoline in 55 gallon drums (600-800
gallons) in metal and plastic drums for 15 years now.

Second, not all metal 55 gallon drums are created equal either. Some have heavier
gauge steel than others and some are made of better quality steel. I got lucky ten
years ago and a friend who worked for a chemical company got me heavy gauge steel
drums that used to hold ethyl ether. These have been great, not one leak yet.
I used to use drums that held hydraulic fluid and I would get 3-4 years before they
tended to start developing pinhole leaks (though I have a couple that are ten years
strong and still going).

The weakest plastic drums I had I got about 3 years out of, these held carwash soap
and they problem wasn't gasoline but UV. The sides that were exposed to daylight
(I have open sided sheds) had significant deterioration and developed pinhole
leaks. Note that this is not full sunlight, just ambient daylight as the sheds are
in the shade. I've got some plastic drums that used to hold IPA (isopropyl
alcohol, rubbing alcohol) and they've held up for 5-6 years so far with no problem.

My heavy gauge steel drums are stored sealed, and as such have kept gasoline good
for as much as 2 years with no deterioration. My plastic drums are used for short
term storage (6 months) and are vented since the plastic doesn't handle pressure
as well.

Rust is a minor problem with steel drums, not really so if you keep water
out of them, and regardless, ALL storage can get dirt in them, so a filter
inline with your pump is a very good idea.

My drums are arrayed around 100 gallon truck mount type fuel tanks with
electric pumps and auto shutoff handles (the setup is about $200 for the pump
and handle and well worth it), so I siphon from the drum to the tank and can easily
rotate my stock that way.

(stabilizers)

I don't use stabilizer. You can, it won't hurt, but if you keep the drums
cool and sealed you won't see problems since most deterioration is caused
by heat and oxygen. ALWAYS use stabilizer for small implement fuel if you aren't
going to use the small engine every couple weeks or so. Gum and varnish
formation is rapid in those small tanks.  Also use stabilizer if you are going
to store gas in 5 gallon containers for more than a few months (you can store
longer in the winter than in the summer, heat and oxygen are the main enemies).

(old oil drums)

Get as much oil out as you can. Then take a half gallon of kero or
diesel and rinse. You can then use that to start the brush pile
or mix in with regular kero or diesel in small quantities.

A little oil in the gas won't hurt small engines or older cars, but some
newer cars can have the O2 sensor messed up.

Then you're GTG. If you have to store the cans in the open without a roof
on them tilt the cans a little to allow water to run off the top and
not pond around the bungs (this is a good idea even if you do have a roof
over them.

Good luck! Rotate your fuel regularly and buy a little more when it is cheap
and a little less when it goes way up. Make the suction tube on your pump
a little short to leave the bottom quarter of the drum untouched and this
will keep you from sucking up dirt and water and will give you an emergency
reserve. Once a year or two completely empty the drums and flush out
water and dirt.

Here is what I do. Try to drain as much of the old oil out as possible. Then put about  1/4 gallon of gas,diesel or kerosene in the drum and put the bung on.Lay the drum on its side and roll it around the yard a few minutes. Usually works pretty well. However, I have never been able to entirely remove all the old dirt/oil etc. Works for me. HTH

diesel is a great detergent.  do like jas said, put a couple quarts into an empty barrel, seal it up roll it around a lot and empty.  you could pressure wash and repeat if need be.