Verdigris, the "greenies"
The backs of many early cameras have bumps under the leather caused by the reaction of chemicals in the leather, moisture, and exposed brass on the camera body. The results are really ugly. The only cure is to remove the leather, clean, flatten, and reglue it. Not an easy task.

These bumps are actually a small, and ever growing chemical deposit, caused by exposed brass areas. Usually body rivets that were not properly covered with paint before the leather covering was applied are the cause.

This problem only occurs on cameras covered with leather. Later Leatherette covered bodies like the S2 never suffer from the greenies.

What to do, is there a cure?
The first thing to do is try to find out the extent of the damage. The bumps are an outward sign of what may be severe damage to the leather. Do the following:

• Wipe a damp cloth over the leather, if it turns green, the leather is quite damaged and should be treated with utmost caution, since it will be very delicate, and may tear easily.
• See how the leather "feels". If it appears dry it will be easier to remove. Leather that has a wet, or soft feeling, often falls apart, and I do not recommend trying to repair it.
• See if the leather is peeling, this is a good sign. If the leather has been reglued using modern contact cement it is a lost cause, do not touch it.

If you decide to remove the leather here is what you do:

• Get the right tools, I have found that single edged razor blades do the trick. I begin the lifting with a sharp X-ACTO knife, but quickly switch to the single edge blade.
• Work very slowly to remove the leather. There is no hurry here! The leather must be removed to the metal, do not allow the blades to cut into the leather itself, but keep the blades pointed slightly down towards the back itself.

  The point is not to cut anything, but to force the blade between the back and the leather, without scratching the back or cutting the leather. By keeping the blade down toward the back you may slightly scratch it, but it's better to put a small scratch on the hidden area of the back than a hole through the leather!

• After removing the leather, set it aside for a complete cleaning, and proceed to clean all evidence of old glue from the back. You can use alcohol or even lacquer thinner in combination with the blade to accomplish this task. Be sure to test any solvent you use in the center of the back, to make sure it is not lifting off existing paint. You can use "0000" steel wool to clean, but be careful not to damage exposed paint areas, that will not be covered by the leather when it is reglued.
• At this time you may want to use "gun blue" to darken any areas on the back you have scratched or that are missing paint. Paint over any exposed brass rivets with clear lacquer or nail polish. This is very important, you don't want the greenies to return. The back is now ready for glue, now move on to cleaning the leather.
• All the debris left by the greenies on the leather must be removed! The leather can be cleaned using alcohol (keep solvents off the front of the leather), do not use any type of polish or cleaners on the leather at this point, since wax may keep the glue from adhering.

  You will have to flatten out the bumps, I use a combination of simply pushing out the bumps with my fingers, and warm water. Let the leather dry thoroughly afterwards. Press it lightly between two sheets of paper towel, let it get enough air to dry. If it curls a bit there is no problem. (update) I do not recommend using an iron, at any temperature, since it is very easy to ruin the leather by causing it to shrink.

• When the leather is completely dry, spray a light coat of clear lacquer on the glue side, to protect and prepare the surface for glue.

• (Recommended) Shellac or shellac based glue. It is hard to know exactly what type of glue that Nikon used on the "M" and later on the "S", but it appears similar to modern shellac-based cements. I suggest using regular amber shellac, which offers less bond and is easily removed using alcohol in the future.
• Water based cement such as "Elmers Mucilage". This offers the least adhesion, but is easiest to work with and remove later, since it is water soluble forever. Not authentic but a good choice.
• Rubber cement, again easy to work with and easy to remove in the future. Not authentic, not my favorite choice, but some collectors I know swear by it. Personally I do not like the rubber odor left on the camera.
• Double faced tape, spray adhesive, or contact cement should be avoided. Nikon used contact cement on the Leatherette on the "S2" and all later cameras, but these cameras never have the greenies because the covering is not leather.

Contact cement is the most likely to cause problems because it provides so much adhesion that every flaw in the leather will be revealed! The leather will have a roughness on the glue side due to the greenie damage. You should use a glue that will not reveal this roughness, by pulling the leather too tightly down to the metal. (See illustration)

When using shellac to glue the leather covering you must coat both surfaces and let them dry till tacky. Then the surfaces can be joined, do not hurry, let the shellac get tacky. I use a few small blocks of wood and rubber bands to keep a little pressure on everything while it drys. Let the shellac dry for 72 hours before removing the clamps.

Final cleaning and polish
Do not over-polish the leather! Usually a soft cloth is enough to bring back the original subtle shine. Do not use shoe polish, it looks awful! A little clear leather conditioner may be necessary, but be careful. If you overdo it, clean with water and try again. Once you a have put on polish there is often little that you can do to remove it.

This is not a simple project but it can turn an ugly camera into a pretty one. I recommend trying it on a junk camera before trying it on your new Nikon M!

Camera storage
Remember improper storage can produce the greenies even on a camera that you collected without them! If you live in a humid environment you must create a dehumidified environment for your cameras. One year in a Florida basement equals 50 in a New York attic. You may want to look into using silica gel in your storage area.