The Military .30/06 Blanks that we use at the American Legion Post has got to be the dirty ammo I have ever used.
Example: July 4 one round was fired in a clean rifle and we are still attempting to get a clean patch from it after several cleaning with Hoppes #9

Maybe it will clean out better with the old military stink finger bore cleaner. The best place to try and bum some is a National Guard artillery unit, with all the close down of units, it seems to get transferred to these units!

Ivan

A lot of the blank ammo is loaded with black powder and there may be paper wadding impregnated with various waxes. Probably the most effective cleaning method will be using boiling water in a bucket with dishwashing soap, insert the muzzle into the bucket, use a cleaning rod with tight-fitting patch to draw the water-soap mixture back and forth through the bore, then repeat in a bucket of clean boiling water. After that a routine cleaning with solvent and light coating of lubricant will keep the bore in perfect condition.

The same cleaning procedure works well with mercuric-primed ammo, neutralizing and removing the corrosive residue.

It had one job.... Go BANG.

It did it.

Job done.

I really don't think cleanliness was part of the equation in producing the ammo.

Just make sure that the ammo states "Blanks"...............

and is NOT a crimped power load used to launch granades , that might be grabbed in error, by some weird chance !!

Black powder ?

At least for U. S. military small arms ammunition, not for a very long time. Depending upon caliber, at least five different "blank fire" fast burning smokeless powders were used.

Rifle grenade propelling rounds for the .30-'06 are not the same as blank rounds and were usually loaded with nearly full charges of regular ball rifle smokeless powders, such as IMR 4895, plus a small amount of black powder.

Please don't take this as me trying to be a smart a*@. I have seen this recommendation given before for cleaning blank fired M1 Garands. How can you get the muzzle into a bucket of hot soapy water and then get a cleaning rod down the bore of an M1. There is no good way to clean an M1 with a rod from the chamber end. Other than using an Bore-Snake or other pull through, M1's have to be cleaned from the muzzle. Due to the rear handguards position in relation to the barrel's chamber opening, there is no good way to submerge the receiver including the chamber without complete disassembly of the rifle down to and including the removal of the rear handguard (not recommended). Turning the M1 upside down in a good padded solid rest and then using the hot soapy water solution (or Windex) with repeated passes of patches & brushes down the bore to the chamber is about the only feasible solution. Follow up with dry patches and then a patch with a light oil of your choice. Depending on how many rounds and how dirty they are, the gas cylinder lock screw may have to be removed to gain access to the gas cylinder for cleaning. Avoid removing the cylinder unless absolutely required, to maintain the tight fit of the gas cylinder on the barrel spines.

You are correct about the M1 rifle, and the same is true of the M14. When I was in the service we detail-stripped (heavily fouled) M14 rifles and cleaned them in galvanized steel trash cans with immersion heaters to keep the water boiling, soapy water in one can and another of boiling clean water. Small parts were placed into wire mesh baskets and immersed in the boiling water. The barreled receivers, operating rods, and other steel parts stayed in the boiling water for several minutes and when removed the water instantly evaporated into the air. Bores were cleaned from the muzzle end using the standard cleaning rod, brushes, and patches. Then a routine cleaning with solvents and lubricants completed the job.

Same procedure was used with the M16 rifles, and proved very effective in removing heavy fouling and all the crud that accumulates in a gas-operated firearm. The early M16 rifles were notoriously picky about cleanliness and proper lubrication. Also, the recesses of the lower receiver can be difficult to clean with the usual tools, and the boiling water left everything pretty much spotless.

Same procedure was used on the M60 and M2 Browning .50 machineguns after heavy range firing. Anyone who has cleaned crew-served automatic weapons after several thousand rounds can recall the chore as tedious at best.

Removing gas cylinder lock screws was never a routine maintenance procedure when I was in the Army. Gas cylinder of the M14 was cleaned with a solvent-soaked patch to remove powder fouling, then swabbed clean with dry patches. Operating rod face and piston were scrubbed with solvent and brush, wiped clean, and very lightly lubed with LSA. I continue to treat my M1 and M1A rifles the same way these days.

These trash can cleaning parties were not daily exercises; the procedures were applied after very heavy firing in training cycles, and usually at the end of a training cycle before weapons were returned to storage. Routine maintenance was done by individual soldiers using the usual cleaning tools (rod, chamber brush, bore brush, patches, etc) with cleaning solvent and proper lubricant application for correct functioning.

Blank cartridges were used in all of our light weapons during various field exercises. The amount of fouling left by blanks was always noticeably greater than any use with standard ball ammo, and cleaning was a serious chore. I remember several training exercises during which I consciously avoided firing blanks so I could avoid the necessary cleaning later.

In later years I have examined Springfield and M1 rifles that had been used for ceremonial purposes (VFW and American Legion posts), and found many suffered from years of firing blanks without a good cleaning.

You can do a pretty good job of cleaning an M1 by pointing the muzzle down and using a small funnel in the chamber to pour hot water down the bore. There are fairly short (6" to 7" long) nylon cleaning rods made which are flexible enough to get into the chamber and a few inches beyond which are made specifically for use with guns where chamber access is limited. I got one of those long ago for cleaning a Remington 740 chamber, which is a lot more difficult to get into than an M1's. I still use it for cleaning chambers of various semiautos and lever action rifles. I have seen similar flexible chamber rods made using steel cable instead of nylon. You can also push a long rod with patch tip attached down the bore from the muzzle, then put a patch (or wire brush) in the tip and pull the rod back from the chamber to the muzzle. Regarding a wire brush, they should always be pulled from chamber to muzzle, never pushed.

This is a flexible cleaning rod using the same idea, but not like mine.