Not all dirt and damage can be fixed, and some collectors may prefer to leave the rule as found, so keep that in mind as you read through here. It is unwise to attempt to clean a rule that is more than 50 years old, unless you are quite comfortable with the process, as the rule may be quite fragile, and the cursor in particular may be easily damaged by careless work, this is especially true with K+E rules.

Every manufacturer makes a point of keeping the rule clean in their instructions, and considerable damage is done by not following these rules, as the cursor and body will become badly streaked, and often permanently damaged. The cursor is the most vulnerable part of the rule, and it should not be allowed to become dirty on any surface. All of the techniques listed here work in real life, and have been thoroughly tested, but the risk is all yours once you start to work on the rule. If you are not sure of your skill in this area, my advice is just not to attempt any cleaning.

My favorite restoration tools, CLICK for a bigger PIC!

Some general things to keep in mind: SUNLIGHT will fade colors and turn the body yellow on virtually all rules, although it can be ussed for a special cleaning trick with some Faber Castell Rules. SOLVENTS will strip off colors, filled and engraved lines, and may damage the cursor material. BE CAREFUL. HEAT can warp any rule. WATER will be absorbed by both wood and plastic rules, and may warp or bind the rule. DON'T SIT ON A POCKET SLIDE RULE, it will be badly warped or broken.

K+E Rule Cleaning & Care

---

WOOD Body Rules
Wood body rules should be stored in a case, out of any severe temperature or humidity changes. Other than the 4058, the K+E wood bodies are made of Mahogany, which is relatively stable, but can be distorted by prolonged exposure to water or sunlight and heat, especially if applied to only an exposed portion of the rule. The scales are made of celluloid (not Ivory as many people think), and will delaminate from the wood if the rule is soaked or exposed to large temperature changes.

Cleaning the engraved scales is best accomplished with a fine scotch brite pad or steel wool (K+E says steel wool, but I prefer the softer pad). Gentle rubbing along the body and slide will remove any surface grime and discoloring, without touching the engraved and filled scales. Many people are reluctant to do this, but keep in mind, this is what K+E recommends, and it works very well if you are careful and patient. Avoid spot rubbing by this method, as it will cause patches of different body color. Once you start this method, you should gently rub down the entire side of the rule to maintain a consistent appearance and reflection.

Cleaning the cursor is much simpler if it can be removed easily, and wiped with a soft cloth or paper towel, dampened with warm water. If it is a duplex rule like the 4081, you may not wish to remove the cursor, and you can slide a piece of white paper under the glass, and gently press on the glass, while moving the cursor along it. This will generally rub any accumulated dirt off of the cursor, and onto the paper. You can help this with a drop of water or Windex on the paper in stubborn cases. K+E used to sell paper triangles for just this cleaning task.

A word of caution: Windex will sometimes dissolve the ink used to mark the cursor line, and create more problems, so be careful when cleaning the surface of the cursor with the engraved and filled line. Also, some older K+E cursors (with a matte, off-white appearance) have a very poor material used as the slider, and it can break or crumble when handled or dampened, ruining the cursor assembly. Spare parts to fix this problem are pretty much non-existent, so be very careful.

You can also use a rag dampened with Windex, and this will help to clean ink stained and dirty surfaces, as well as the edges of the slide and body. There should be no dirt in the sliding portion of the rule, and a rag with a small bit of Windex will help to remove any accumulated dirt and abraded material. I do not recommend waxing the rule face (as it collects and traps dirt, especially under the cursor), BUT you may wish to lightly rub the faces and edges with a very small amount of Pledge to give a shiny appearance if the rule is mainly for display. Wax, or preferably Pledge, will often bring out the wood highlights in a very attractive way on edges of rules such as the 4053 and some 4081 rules. Anything in the sliding area of a wood rule generally increases friction and binding, but the nature of Pledge is to make the surface very slippery, and it works well as a lubricant. The best possible technique is to have this area as clean and free of rough edges and burrs as you can make it. If this area is rough and sticks, and it has already been well cleaned and the gap is correctly set, a very light rub with Pledge may improve the action.

The case should be cleaned with a damp cloth and some Windex for stains and marks, and once dry, rubbed with a good leather polish or Pledge, and shined. Leather will dry and crack if not moisturized by some method, so don't ignore the case. Often, a previous owner will mark up the inside flap with a name, address, school, etc., making the case quite unattractive. it is possible to remove SOME inside flap markings by gentle abrasion with sandpaper (I use a slow belt sander), to remove the top layer of the leather, but this is not for the faint of heart. Never attempt to remove the markings with any solvent, or you will almost certainly stain and ruin the case.

---

PLASTIC Body Rules

These rules should be stored in a case to protect the cursor, and not exposed to any severe temperatures or extreme sunlight. Xylonite rules can be distorted, or discolored by prolonged exposure to water or sunlight and heat, especially if applied to only an exposed portion of the rule. Unlike wood rules, plastic body rules cannot delaminate, and are made of a single solid material.

Except for the painted scales on the K-12 rule, the 68-1292, cleaning the engraved scales on a plastic body rule is best accomplished with a fine scotch brite pad or steel wool (K+E says steel wool, but I prefer the pad). Gentle rubbing along the body and slide will remove any surface grime and discoloring, without touching the engraved and filled scales. Many people are reluctant to do this, but keep in mind, this is what K+E recommends, and it works very well if you are careful and patient.

Watch this rule return from the dead below.

Washing in warm water and Palmolive dish detergent can help de-grime some plastic body rules, and cleans out many crevices.

Notice how the surfaces are restored with just
some gentle rubbing and a scotchbrite pad.

How the parts look when you are finished.
Yes, it's the same rule as shown at the top!

A word of caution: Windex will sometimes dissolve the ink used to mark the cursor line, and create more problems, so be careful when cleaning the surface of the cursor with the engraved and filled line. Some plastic body rules, especially the 4181 and Doric rules, used a scale fill material that dissolves in Windex, resulting in a smeared appearance when the rule is washed with Windex.

You can also generally use a rag dampened with Windex, and this will help to clean ink stained and dirty surfaces, as well as the edges of the slide and body. There should be no dirt in the sliding portion of the rule, and a rag with a bit of Windex will help to remove any accumulated dirt and abraded material. I do not recommend waxing (heavy wax) a plastic rule for any reason. Anything in the sliding area of a plastic rule generally increases friction and binding, and the best possible technique is to have this area as clean and smooth as you can. If the rule sticks, and it has already been well cleaned and the gap is correctly set, a very light wipe with dry powdered teflon or a very small amount of Pledge will improve action, and will not mark the rule.

The case should be cleaned with a damp cloth and some Windex for stains and marks, and once dry, rubbed with a good leather polish or hard wax, and shined. Leather will dry and crack if not moisturized by some method, so don't ignore the case. Often, a previous owner will mark up the inside flap with a name, address, school, etc., making the case quite unattractive. it is possible to remove SOME flap markings by gentle abrasion with sandpaper, to remove the top layer of the leather, but this is not for the faint of heart. Never attempt to remove the markings with any solvent, or you will almost certainly stain and ruin the case.

Sun/Hemmi and POST Bamboo Rules