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topic 0757

Restoring an old National Cash Register

A discussion started in 1998 but continuing through 2017


Q. I'm restoring a National Cash Register with a case made of very ornate red brass. Being almost one hundred years old, the case is tarnished to the point where it is virtually black. Many polishes will remove the tarnish on the flat surfaces, however in the deep crevices the tarnish just can't be reached with polish. Is there some type of chemical solution in which I can dip the parts in order to remove the tarnish.

Thanks for your time and consideration.

Tom D [last name deleted for privacy by Editor]
St. Albans, Missouri


A. Tom,

Get a bottle of Tarn-X [linked by editor to product info at Amazon]. This is a chemical cleaner for brass that will remove the tarnish without damaging the brass. Just dip your parts into a bowl of this solution and use a soft bristled brush to scrub the recessed areas. Unless the surface is sealed in some manner (clear lacquer or polyurethane) the brass will tarnish again in a few months. Good Luck!

Tom S [last name deleted for privacy by Editor]
- Reading, Pennsylvania

A. We appreciate Tom's help, but this information is not entirely accurate. The Tarn-X site includes this FAQ:

"Is Tarn-X safe to use on brass?
No, Tarn-X is not safe to use on brass. This is because brass is an alloy of copper and zinc, and the acids in Tarn-X effect zinc."

However, there is a separate product called Tarn-X Brass Glaze.


Ted Mooney, Teds signature
Ted Mooney, P.E.
Pine Beach, New Jersey


A. Tom: I have tried Tarn-x and have had little success except with might try liquid toilet bowl cleaner (toilet bowl cleaner [linked by editor to product info at Amazon]) which contains Hydrochloric Acid...wash off as soon as you use it but it will definitely remove tarnish from Brass and copper. I apply it with 0000 steel wool [linked by editor to product info at Rockler] which won't scratch the metal. Needless to say (but I'll say it anyway) wear protective gloves [linked by editor to product info at Amazon] and don't breath the fumes. After you remove the tarnish polish with a Cape Cod Metal Polishing Cloth [linked by editor to product info at Amazon] and watch the shine come out!

Good luck...

Glenn H [last name deleted for privacy by Editor]


A. It is possible that the original finish was a lacquer, which was thin on the flat surfaces, thicker in the textured surface. Soaking the part in a hot alkaline solution, or trisodium phosphate [linked by editor to product info at Amazon] or Sodium Metasilicate or some solvent to remove this lacquer before attempting to polish it might help.

tom pullizi signature
Tom Pullizzi
Falls Township, Pennsylvania


Q. I have a 1 oz. bottle of Tarn-x silver glaze and I've had it for a while and it is all gone now. All I wear is silver jewelry and this is the only stuff that I really like to use but, my problem, is that I don't know where I got it in the first place. Do they still make this product? If so could you please tell me where to obtain it?


Melisa A [last name deleted for privacy by Editor]

Ed. note: Apparently there are different Tarn-X products, Tarn-X [linked by editor to product info at Amazon] "Tarnish Remover" and Tarn-X Silver Glaze [linked by editor to product info at Amazon].


Q. I have a old National Cash Register with the same problem. I have tried everything as well.


Jim Decker


Q. I'm an ex NCR Tech from the old days and would like current news to help in restoring an old brass Class 452 I got for Christmas.

Thank you.

Jim R [last name deleted for privacy by Editor]
Anchorage Well and Pump Service


Q. Is it advisable to apply paste wax following the cleaning of brass? My goal is to reduce the frequency of polishing my large brass candlesticks.


Dorothy E [last name deleted for privacy by Editor]


A. Try using ketchup as a brass cleaner. I don't know why, but there is a chemical reaction and the brass cleans up beautifully. I have just finished stripping and "renewing" 6 pairs of ornate engraved brass door knobs and key hole plates which had been painted over many times since the early 1900's. I used a commercial stripper, then rinsed with water, dried, and soaked in ketchup for 30 min. or so. I used a firm tooth brush as well as other dental cleaning instruments (available at local drugstores) to get into the engraved/and or upraised sections and fine steel wool to finish and shine. Time consuming, but well worth the effort and very inexpensive also.

S. Szigli
- Taber, Alberta, Canada

A. Hi. Ketchup is aggressive on brass because it contains vinegar and salt. It may be fine for big robust items but can actually damage very fine detail.


Ted Mooney,
Teds signature
Ted Mooney, P.E.
Pine Beach, New Jersey


Q. I checked on Tarn-X for an antique brass bed I'm working on but the directions on the bottle specifically stated not to use the product on brass. Is there more than one kind of Tarn-X? If so, where might I find the product acceptable for use on brass? thanks!

Candy H [last name deleted for privacy by Editor]
Ozark, Missouri

Ed. note Yes, Candy, there are (at least) two different Tarn-X products; we hear there is a "Brass Glaze", but that is hard to find.


Q. I am looking for something to remove the lacquer finish from a brass piece. I have a vintage brass light which is not lacquered and has therefore obtained a nice tarnished finish, attached to a new brass rod and ceiling plate which is lacquered and won't tarnish and therefore looks too new next to the vintage piece. Is there something I can wipe on the new brass to remove the lacquer so it will tarnish and match the old brass? Also, if the new brass piece is just brass plated, will it still tarnish? I appreciate any feedback you can give me.

Suzanne C [last name deleted for privacy by Editor]
Cummaquid, Massachusetts


A. Soaking the lacquered pieces in paint remover or lacquer thinner [linked by editor to product info at Amazon] should remove the coating. The brass will tarnish, but if brass plated steel will tarnish, then rust, in short order. You may need solid brass to match the old piece. Or at least, heavy brass plated steel.

Tom Pullizzi
Falls Township, Pennsylvania


Q. Any info out there about cleaning nickel plated brass cash register?

Sheila J [last name deleted for privacy by Editor]
Long Beach California


Q. I have a brass bed with a lot of pitting. Brasso [linked by editor to product info at Amazon] makes it bright. Any suggestions, please?

Stuart D [last name deleted for privacy by Editor]
Naples, Florida


Q. I have copper hardware for kitchen cabinets that have tarnished. I need some tips on what chemicals I should use to restore them. They do have a small design on them that I don't want to lose. Thanks

ROB F [last name deleted for privacy by Editor]
Morton, Pennsylvania


Q. I haven't had much luck in applying a spray coat of clear lacquer on exterior brass lighting fixtures to prevent tarnishing.

Has anyone been successful with this approach? Has anyone tried to coat polished brass with Tung Oil [linked by editor to product info at Amazon] and then oven dry it?

Tim G [last name deleted for privacy by Editor]
Clifton Virginia

Ed. note: G.J. Nikolas [a supporting advertiser] can no doubt advise you on that issue.


Q. Help...Brand new lacquered brass switch plates tarnish nearly black within a day or two around the edges. This only happens on one set of switches in my house. I have checked and there are no chemicals in the primer or wallpaper that would cause this reaction. Also, the electrician has checked the switches and they do not run hot. Draft stoppers slowed down the tarnishing (now it takes months for it to destroy the new plate). What type of gases, etc. could cause this phenomenon to occur.

Caroline B [last name deleted for privacy by Editor]
Riverdale, Iowa


A. Cleaning of brass is not easy where there are surfaces not able to be reached by normal methods ( polishing by hand etc using rag or cloth ).

A liquid type of Cleaner is required , for dipping or brushing or spraying .

After trying to clean brass cartridge cases for reloading a few items were tried , Hydroxyacetic acid as in the following product ( G96 BRASS CASE CLEANER , stock # 1135 . G 96-Design Tech Carlstadt NJ) Worked well , can't find it anymore. Acetic acid can also be used , ask the supplier for instructions for use .

I found a mild cleaner that is cheap , freely available and it works for me , normal VINEGAR . I dump about 100 9 mm cases in a pint of vinegar for a few minutes and rinse off in water and the cases are much cleaner -- not perfect but a good compromise .

Raymond L [last name deleted for privacy by Editor]
Bloemfontein, South Africa

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