I speak not of hard street drugs, nuclear waste, or whatever it is they made Rosie O'Donnell out of...
No gentle readers, I speak of... COSMOLINE
There should be a "Frau Bleucher" moment there when I say that... just imaging dramatic music and a crash of noise or something....
A few days back, someone asked me a question about how best to deal with cosmoline, and since 1. I disagree with much of the "conventional wisdom" that is out there about the stuff, and 2. I haven't seen anyone posting about it recently (not since Surplusrifle.com almost shut down a couple years back and released their archives on CD) I figured, sure what the hell why not.
Alright first, what exactly IS cosmoline?
Basically cosmo is the brown and sticky crap left over when they've cracked all the lighter fuels and solvents out of crude oil. It sticks to everything, and it's a pretty damn effective moisture barrier, so it's a pretty good protective agent against corrosion.
Most major military establishments of the past 120 years have used cosmoline or something like it, to protect their inventories of various metal bits (not just guns. The Navy has been encasing parts in cosmoline for as long as the stuff has existed... you know, having all that salt water to corrode stuff and all).
So, if you have any interest in buying surplus military weapons or gear, you are eventually going to come into contact with cosmoline.
Many of us have "fond" memories of stripping cosmo off our new pride and joy... for hours, and hours... sometimes days or weeks... before we could fire them.
Me and four friends once decosmolined 3 Yugoslavian SKS's one evening in the parking lot of a motel in north central Texas; by sticking them upright into the grass by their bayonets, and repeatedly spraying and scrubbing them down with brake cleaner until we could disassemble them enough to get the smaller bits into cleaning tubs, where we used MORE brake cleaner (about 3 cans worth for three rifles) to try... unsuccessfully I should add... to get enough cosmo off the things to make them shootable for the next day.
Brake cleaner works, but it isn't ideal. Especially if you're just spraying it, brushing with cleaning brushes, and wiping with shop rags. That's just how nasty and persistent cosmoline is.
Have I mentioned that I LOATHE cosmoline with a passion as fierce as the burning of a thousand suns...
Sadly, my loathing is insufficiently hot to actually melt cosmoline off of anything...
Ok, so how DO you get rid of the stuff?
Well, first let me point you to the "Maintenance" section of the aforementioned surplusrifle.com site. They've got a number of guides to decosmoing, as well as just a bunch of good and useful info in general.
Most of what I'm going to say is probably roughly said in one or another of those guides.
But I'll share with you my own personal advice anyway.
The absolute best way to deal with cosmoline is with a hot recirculating solvent at pressure. A heated spray industrial parts washer will do the deed faster and better than anything else. You can decosmo an entire rifle in minutes, including the stock (though you're still going to have to hot box the stock to deal with weeping).
Unfortunately most people don't have the kind of parts washing setup that needs. A decent setup might run you $3000 to start, up to over $10k. That said, you might have a friendly local mechanic or machine shop who does, and will let you borrow or rent time with one.
My recommendation though is the second best way I know of.
The next best way is to use hot, pressurized steam, and a hot water TSP bath. Use the steam to soften stuff up, then scrub a bit with tsp in the tub, then more steam, then more tsp etc...
You don't NEED to use TSP, but it's one of the more effective degreasers out there that you can use in a hot water bath. Also, it doesn't outgas nasty stuff, or blow up, when heated. You could use plain water, but adding a surfactant degreaser like TSP will make your life a lot easier.
If you start off with very hot water to begin with (heated up on a stove or propane burner to over 160 degrees... even up to boiling if you like, and have a cleaning tub that can take the heat) and work quickly, the steam heat will keep things hot enough you don't need a burner under the water/degreaser batch when you're doing the rifle.
The whole process takes a fair bit of effort, but it works VERY well. The important thing is to get the entire mess above 140 degrees, no mater what kind of solvent you're using. Cosmoline melts at between 115 and 125 degrees unless it's fully hardened. When fully hardened it doesn't melt til 130 and 140, and you may need to chip off or scrape through a hardened surface layer that won't melt off at all.
A standard household steam cleaner, if it has a pressure wand or nozzle type attachment, will do the job just fine (a steam upholstery cleaner/drap cleaner or stem iron won't give you enough pressure, or enough volume). My wifes cost $140, and it's overkill. There's a $60 handheld one you can buy from any department store, or amazon, that a lot of people have had great success with.
If you have a propane burner and a pot or tub big enough to hold whatever you want to decosmo, you can also just boil the stuff off.
You can use plain water, but it's much more effective if you put TSP in it. Or washing soda. Or any surfactant of any kind.
Just make sure you rinse with clean water, and then oil the hell out of the piece IMMEDIATELY after you finish cleaning.
Oh and do it outside. There's a risk of fire, and a certainty of a smelly scummy mess.
DO NOT BAKE COSMOLINE OUT IN AN OVEN.
Oh, it can work... In fact every time I see a cosmoline thread, somebody recommends it... but it's a BAD idea.
Cosmoline starts fuming volatiles out above 220 degrees, and will flashover at 350 degrees. Even if you set the oven to 150 degrees, the heating element when it cycles on is going to heat up to over 500 degrees, and that is enough to cause flashover... possibly when you open the oven door to check on everything and a nice burst of fresh oxygen rushes in...
Seriously, if you bake it out in an oven, it is entirely possible you will blow up your oven. Even if you don't, fumes will permeate everything and make them smell like cosmoline for frikking eternity.
You don't want your oven, or your kitchen, to smell like cosmoline, trust me.
Similarly, don't use gasoline to clean off cosmo.
A lot of people use gasoline, because their corporal in 'nam showed them it worked better than the "official" procedure etc... etc...
Generations of servicemen had been assigned to clean cosmoline off rifles as a punishment duty or a "character building exercise". Gasoline was the best way the average private had easily available to them to make it easier (Air Force airmen, and Navy seamen have a lot more access to more exotic solvents).
Sadly, soaking and scrubbing in gasoline isn't a great way of doing it. It's better than trying to use bore cleaner or brake cleaner, but not much.
If you don't mind a big fire, you can actually burn/boil/melt the cosmo off with about 10 gallons of gas in a steel drum (a half barrel is best)... but that's dangerous as hell, and only works on bare metal or parked finishes. Bluing or any kind of paint or epoxy will be screwed up by it. Plus, these days, 10 gallons of gas aint chicken feed.
I've heard guys say "wont that warp the gun or detemper the steel or something?" Nah.. wet gas burning doesn't get that hot for that long. The real problem is the gas boils, and the vapor can make some seriously cool... but horribly dangerous, great big frikken fireballs.
Really... it's a bad idea. Don't do it... at least not with anything you care about... like your eyebrows.
Then there's the long term, slow, but low investment and low effort method.
The steam cleaner method definitely works the best, but it requires diligently working at scrubbing and steam cleaning, up to your elbows in hot water and solvent, getting filthy etc... etc...
I'm lazy. I don't feel like that much work. Unless the thing is totally gummed up to the point where I can't disassemble it, I don't really want to break out the tub and steam cleaner.
When I need to FULLY decosmo something (especially if it's a small to medium sized piece with no wood), I usually pull it out of the stock, detail strip it, and put the action and parts in a piece of pipe or a tub, painted black, sealed all around, and filled with acetone, MEK, TSP, DCM etc... (any number of solvents will do it. Just use one that is OK with the type of container you're using and wont dissolve any parts or finish from the gun).
Then I leave it out in the sun for a few days, or put it in a hotbox (a sealed box with three or four 100 watt bulbs or a flameless heater, preferably one with a fan, and some insulation), and agitate and flip it periodically.
Outside of course. Explosive fumes and all.
It takes a while, at least a couple days to maybe a week, depending on how badly gunked up the weapon is, and how hot you get your container; but it requires very little physical effort and actual scrubbing, and gets the weapon very clean.
With the stocks, you generally need to do it without the solvent, since they'll usually eat the finishes, and may swell the grain of the wood. Unless of course you don't care and plan on refinishing anyway, in which case, solvent away.
Otherwise, it's hotbox for a few hours, then wipe it down with a mild solvent, then hotbox, then solvent etc... for about a week, till all the cosmo weeps out.
