Removing Stains from Raw Leather

Leatherworking can be very rewarding but sometimes when we least expect it we can be blindsided by something that happens to our project. I have had this happen to me a number of times over the years that I have been doing hand-tooled leatherwork. I can tell you that it is not fun when you have to redo a project that you have many hours completing in the first place.

I have had well-meaning people pick up a project to look at it and leave fingerprints on it. It is a little like Steve Urkel from the old TV show asking, “Did I do that?” People do not realize that oil and dirt get on their hands even if they have not been working on their car or lawn mower. I have had fingerprints on leather that would have probably been good evidence in a criminal case. In some cases, it does not mean that all hope is lost, just that you might have to do a little cleanup to get rid of the spots. By the way, most of the fingerprints were probably my own.

I mentioned in a post a while back that there is a product that can be used to get rid of most stains on the surface of unfinished leather. “Unfinished leather” is the raw leather, whether stamped or not, when it has not been treated with a lacquer or acrylic finish or oil. The product of which I am writing about is Oxalic acid. Depending on who you might talk to or which web site you might visit, you might find it being called “wood bleach” or “leather bleach.”

I really do not care what you call it but you may have to do so research to locate a supplier in your area. The oxalic acid that I purchased came from a pharmacy approximately forty years ago. It came in powder form and in a quart jar. All I had to do was mix it with water and make sure that I did not get too much powder in the jar to begin with. What I have seen for current suppliers of the oxalic acid is that some of the lumberyards might carry it for use with special projects. You might also need to sign your life away to be able purchase it because it is poisonous. You might need to tell the person selling you the product what you plan to do with it.

Now with that out of the way, a little goes a long way. I have a pint jar that I have used for many years to mix and store my mixed oxalic acid. I do not have an exact recipe for the mix, so I would recommend using one-half teaspoon for a half pint of warm water for easy dilution. Be sure to experiment on a piece of scrap leather before you use this recipe on a project that you have spent a lot of time stamping. The reason being is that oxalic acid itself will add some color to the leather. Making it too strong may strong may add more color than you would want.

Always wear rubber gloves when using oxalic acid. Use a clean sponge that you can dip in your jar to soak up some of the liquid. If you were to apply a bit of the oxalic acid mixture to a small spot on a piece of scrap leather, initially, it will look as if you had applied water only. After the spot dries, you will then notice how the color of the leather has changed on that spot. The best way to avoid the spotting is not needing to use the oxalic acid. When it is necessary to use oxalic acid, you do not want to apply it liberally, especially if you have done a lot of carving and stamping on the project. Getting the raw leather too wet can sometimes cause some of the deeper stamps to lose some of their depth, especially the background.

The other thing with oxalic acid is that you do not want to apply it to the stained area only. If it will darken the leather in the area where it is applied then you will want to apply it lightly to the whole piece of leather to eliminate the spotting. Bleaching out a stain in raw leather is a pain because it can change the look of the whole project. Imagine getting a dirty fingerprint on a project that had one or more overlapping pieces. To make everything look the same you would have to apply the oxalic acid to each piece of leather. This could create a lot more work, especially on a project with multiple layers such as a purse.

There are some stains that are almost impossible to get out of raw leather. Two of the worst stains that I know about are ink and blood. I believe I mentioned them in an earlier post but it does not hurt to give you a reminder. With that stated, there are some other “stains” that you will not be able to get out of leather as well. You will find that some leather comes with built-in stains or coloring that cannot be removed by bleaching with oxalic acid. I have had leather like that before and I tried to work around it or incorporate it into a portion of the pattern with a lot of stamping.

Raw leather is sensitive to light. I have had projects that I inadvertently left out where the light could hit them before I had the time to finish. One time I left a leather box unprotected that I had tooled, sewed, and babied along to get it all done for an award at a big rodeo. I put the straps around the box to make sure that it held its shape and I forgot to put the cloth covering over it before I left for the day. Enough sunlight came through the frosted windows to darken the leather. There were stripes where the straps were covering the leather, which prompted a complete dye job.

The photos below show my attempt to demonstrate what direct sunlight can do to leather. The photo on the top shows how I set this up. I cut a small piece of leather and placed it on top of a larger one. The second photo shows the after effects of the leather sitting out in the sunlight for a few hours. You can see the light spot in the center of the piece of leather. This one is not as dramatic as I had hoped it would be, but I can promise you that some leathers will almost sunburn.

Small piece of leather on top of larger one - sunlight demonstration

Leather after exposure to sunlight - notice the darkened area.

Sunlight is not the only light source that will change the color of unfinished leather. Fluorescent lights will affect the leather as well. The thing that you want to remember is that leather is skin and that it is much like our skin, it will burn. It may not be because of the leather being skin as much as it is the chemicals that were used in the tanning process. It is possible that it is those chemicals reacting with the light that causes the darkening of the leather. If you have some scrap leather, you might want to experiment to see if you can duplicate the results of my little test.

In summation, you cannot bleach out the darkened areas caused by light on leather. The best way to avoid having this happen is to keep it covered or if you are letting it dry, make sure that you check it periodically, cover it with something that will not transfer any color, or just turn it upside down on a clean surface. It might take a little longer for the leather to dry properly if it is turned upside down.

Leather is not photosensitive like film that we used to use in our cameras. It will take a few hours for light to have a major effect. Just a short anecdote about my leatherwork: Almost twenty years ago, I made a photo album for a man and it had a lot of figure carving on it. Figure carving is carving animals and objects such as a cabin or a covered wagon. (There are many other figures that can be carved; those are the only examples that came to mind while preparing this post.) 

Anyway, I had completed this photo album and was going to take it to the local shipping store when I noticed that there was a faint amount of color in the lacquer. I was quite concerned when I found it because I had been very careful about not exposing it to anything before I took it with me. What I had done was, I was working full-time at job, and I left the photo album in my pickup, inside a plastic bag. What I did not think about was that I had printed a receipt on my color printer and placed it on top of the photo album inside the bag. What I saw on the front of the photo album was a copy of my logo in in the lacquer finish. Fortunately, it was not so dark that it was noticeable to most people. I may have been the only one who saw it. At least I hope I was. Another lesson learned.

Let me know if you have any questions or comments. I would love to hear from you!

Have fun!