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How to clean files

I know I have read about something you can clean files with beside
nitric acid but I can’t remember what it was or where I saw the

Can anyone tell me how to clean and recondition heavily clogged
files? I have so many files that just don’t seem to work as well as
they did and I would like to be able to salvage some of them and not
have to buy new ones!

Marilynn Nicholson

Hi Marilynn

I will assume you tried a file card and short bristled stainless
steel brush. It is time consuming, but I use brass to slide between
the teeth. Most of the time I use rifle brass, but pistol brass works
ok also. Brazing rod might be more available for you unless you shoot
or know some one who frequents a shooting range, you can find brass
all over the ground usually. Place the open mouth at an angle to the
tooth of the file and slide parallel to the cut. It will take a few
times across to cut the pattern into the brass, but once it is there
it works pretty good. It won’t get all the way to the bottom of the
tooth, but it will recover a dirty file even with metal packed in,
also works on rust.

This is assuming that cleaning is the problem and not dulling of the
teeth. Anyhow, that’s my $0.02.


A good ol’ File Card/Brush. It’s a small hand held wooden tool with
100’s of little metal bristles. I read somewhere that brass can be
used as well.

Just take a bit of brass stock and rub it on the file. It will
create grooves in the brass and thus contour to the file cut, pushing
out the debris. I also use a bit of chalk or talcum powder to help
minimize the clogging. Also, try smacking the file on your bench pin
every dozen or so strokes, to throw out little bits of clogged

I have just steamed the heck out of them to clean them, But a close
friend showed me how to make them like new by using a tungsten
carbide scribe and cleaning each channel and burnishing up a new
sharp edge. Try it you will like it.

James Kallas Santa Fe NM

I thought someone else would mention this, but… You can rejuvenate
files quite a bit simply by tossing them into pickle. If it’s used
pickle, they’ll come out copper plated, but that doesn’t seem to do
any harm that I can tell. It also doesn’t seem to hurt the pickle–
just don’t do it while other stuff is in there.

If my files were clogged with metal, I might try tossing them in the
appropriate etchant for that metal first (ferric chloride for copper
or brass, nitric acid for silver). Any reason not to do this? I
can’t get myself to sit and pick at a file one groove at a time!


Terry, I’m betting you know this but for those that don’t: Really
soft copper works well too, and if you have a circa 1970’s pair of
desert boots, the crepe rubber soles can be recycled into handy
shapes and then run with the file’s teeth to pull small fine
particles out of clogged filesThe crepe can also be cleaned with an
old sanding belt that isn’t good for anything but cleaning soft
rubber! Just sand the stick, triangle, square, etc. of crepe to
reveal new material and they’ll last as long as you have something
to hold onto ! Another trick is graphite packing coils- they too will
clean a file and “condition” it so that metals will tend to fall out
rather than load the teeth. reapplication is necessary only every
month or so - providing you at least card your files before storing
them after each use…! rer

Files should be cleaned of embedded metal before “sharpening” them
by placing in an acid bath. Otherwise you can end up with some
strange and possibly not so effective tooth patterns as the etching
rate will vary around the contaminated areas. Ferric chloride and
nitric acid both attack the iron in the files as well as copper and
silver. Also if you are using pickle that has copper dissolved in it
as soon as the copper plates the files (almost instantly) the etching
action on the steel will stop defeating your intention of sharpening
the file. It may seem to work better for a short period because the
copper will act as a lubricant as long as it is there. To get the
full effect use clean acid solutions to “sharpen” files this way

To clean the files of embedded metal drag or push a piece of copper
sheet about 1 mm thick in the direction parallel to the teeth. this
will easily remove the offending material rapidly.

James Binnion
James Binnion Metal Arts



Terry, I'm betting you know this but for those that don't: 

I did not, had not tried it I had the brass handy so copper was
never considered. The Crepe idea is new, I wonder if a belt cleaner
would work. The most promising is the carbon product to act as a
lubricant to keep the file tooth from packing with metal or other
material to begin with. I am thinking that perhaps a carbon stir rod
or arc rod would work also, and after application work it over with
an old tooth brush to get the material down into the tooth real well.
Just so happens I bought a new set of files and have not set them to
metal yet. They are #4 cut and I suspect because of the fine tooth,
will be a bugger to clean.

Thanks for the tip, heading to the shop to implement.


I used one of those crepe bars used for cleaning sanding belts & discs, & now my file is really , really gummed up! Tried removing the Gum with brass sheet, wire brush file cleaner - nothing seems to work. If time is money, I’ve probably spent a files worth of time on this already.

I use Evapo-rust

Seems t work well. My favorite solution is a new file. I have a #2 ready for the new year…Rob

Hi Rebecca, In regard to using graphic packing coil to clean and condition files: I know that there are myriad bases for the stuff, from PTFE to cotton to the most common, the narrow diameter flexible graphite string packing coils. Could you please tell me what type you use (or for what industry/use/ or intended application you source)? Thanks very much.


Sheila, That is really good to know - thank you for the warning. Jennifer