Cleaning Combo Squares ?

[Doug Shepard]

I've got a couple of 6" combo squares that need to be cleaned with something but I'm not sure what. One is a roughly 30 year old Starrett that has a patina so dark it's tough to see the etchings well. The other is a maybe 15 year old BCTW in better shape but also getting a dark patina. I dont think I want to scrub these with anything at the risk of leaving scratches. I've seen a couple of threads on cleaning old saws recently that suggested soaking in citric acid to clean them up and that apparently doesn't have any negative impact on the etchings but that maybe tends to darken the underlying metal which is what I'm trying to clean up. So what's the best thing to soak these in to clean up some of that underlying patina so that there's better contrast with the rule lines?

[Paul Steiner]

Every year I have to clean my schools steel rulers and combo squares. Greasy student fingers rust them quick. I use steel wool and wd-40 or silicon lubricant. Some 00 or 000 should not leave any noticable scratches. Some people say leave the patina, but its a starrett it wants to be used.

[Chris Tsutsui]

If I was going to use the tool myself, then I would go ahead and use an abrasive to remove the patina. If steel wool doesn't work, then I would just go ahead and use 400 grit or finer wet sand paper with wd-40 as lubricant. I'd use a hard sanding block so as not to round over the edges.

I have a large amount of 80's and 90's starrett and mitutoyo machinist tools I need to sell on ebay.

I'm having a tough time debating if I should use a slight abrasive to clean these, and then some lacquer hobby paint to fill in the text again.

All of them are engraved and personalized by the previous owner who passed away.

I'm thinking of just leaving them as is and let the next owner decide if they want to restore it. However I think some of them will sell better if I restore them to look like new.

[Paul Atkins]

Doug, I would do as Chris says.
Chris, if you are just going to sell them, time is money. Try cleaning one and see what happens. Might not be worth the time. Might be surprised. I'd rather clean my own and think I got a good deal for a 'dirty' one.

[sean m. titmas]

to clean off pitch, gunk, patina and most anything else from any metal tool or blade i will soak the tools in some oven cleaner. after about a 6- 10 hour soak in a plastic container or metal pie plate there will be nothing left on the tool and no scratches either. if there are some stubborn areas than you can soak it overnight or use a 3M Scotch Brite pad to loosen it with no danger of scratching. Make sure you protect the metal with something like WD-40, silicone, or Bo-Shield after the cleaning otherwise it will develop surface rust.

[Josiah Bartlett]

I like the patina. I just rub a little wax or chalk over the markings to make them show up better.

[Doug Shepard]

I'm liking the sound of the oven cleaner approach. Think I'll pick some up and try it. There's no rust on either of these. It's just accumulated grime, pitch, etc.
Thanks.

[Chris Tsutsui]

Oven cleaner works well on saw blades as well.

I would look for a bulk liquid type in a container and not get the "easy off" spray types and end up spraying an aerosol into a tub to fill it up.

Just make sure to test it out on one tool before you throw the whole batch in there.

My brother in law threw all of his valuable collectabel coins into a tub and put in a mixture of harsh chemicals thinking he could clean them all.

He let it soak too long and ALL of the coins have been completely ruined...

[Gary Muto]

Doug,
I just read an article in the October issue of American Woodworker about fixing water stains on furniture. There was an inset photo that showed a plane blade that was rusty. A 24 hour soak in oxalic acid cleaned the rust off with no damage to the steel. Maybe this would work for you. I don't know if it's less harsh than oven cleaner either.

[Steve Rozmiarek]

Chris, I wouldn't clean those before you list them. I like the patina on mine. Makes it feel like I'm using something with a long history, and I find that inspiring.

[Myk Rian]

I use the same thing I use on my iron tops. Bar Keepers Friend. Just make a paste with water, and use a rag to apply it. Rinse it off.
No scratches, and looks great.

[Jim Newman]

Sandflex Hand Blocks made by Klingspor is the greatest things since sliced bread for cleaning surface rust "patina". They come in Coarse, Medium, and Fine Grit. It makes the steel look brand new. I used these to clean up some Starrett rulers I got on ebay a number of years ago. Follow it up with Boeshield T9 to protect the steel and you are good to go for another lifetime of use! BTW I have been a chemist for 30 years, but try to keep things simple if I can. I do electrolysis and the other ways mentioned but for what you have, the Sandflex blocks work really well with no wet mess. You can get them at a local woodcraft store or order them online.

[george wilson]

You might find that the finely engraved markings could become larger,and "eaten out" looking from soaking in harsh chemicals. Over hand sanding also may cause those fine engraved lines to vanish near the edge of the blade,from the edges being slightly rounded over from the sanding.

[Doug Shepard]

Well I was going to pick up some oven cleaner tomorrow while grocery shopping but had some time today and some Barkeepers friend already here so Myk's suggestion sounded worth a try and it worked great. I mixed up a thick paste and worked over the rules with an old toothbrush. Took about 10 minutes for the Starrett which was so dark that reading the rule lines was getting very difficult. Only took about 2-3 minutes for the BCTW. After rinsing and drying them off good, I gave them a good wipedown with Ballistol. Both of them look almost as good as new now. A nice satin chrome finish with just a hint of patina and very legible. Kicked myself afterward for fogetting to take some before and after pics.