Innovation of the Month: Pro MotorCar PrepPen

By: Steve Larsen

Half a dozen years ago, or more, I acquired a PrepPen, although I’ve no idea how or why. It sat around untouched for a few months. One day when replacing the batteries on a rarely-used flashlight, I grabbed it to see if the PrepPen could remove the corrosion inside the flashlight. Presto! Clean terminals. Soon I was on a mission find more uses.

The device is not complicated. It resembles a short, fat mechanical pencil which, instead of black lead, pushes out a tight tube of white glass fibers, each finer than a human hair, razor sharp and very strong. Turn the wheel one way and it extends the glass fibers, the business end of the PrepPen. Turn it the other way and it retracts.

Once I started looking, opportunities popped up everywhere, particularly related to removing corrosion or rust build-up in small, hard to reach places. It makes quick work of a rusted screw, not just the Philips head but the threads as well. One day the RJ11 (phone-type plug) powering the radar detector on my V-Strom stopped working. A mild brush with the PrepPen on the RJ11 connector leads and then on the edges of the fuse and it was working immediately again.

But then it ran out and try as I could, I never found it again. And I looked! I tracked down a rumor that Napa carried them. Someone said, “Try Marine supply stores,” but no luck. I kept the old depleted one in my desk drawer for several years, occasionally doing an Internet or Amazon search, but nothing ever came up. A few months ago I searched again. This time – BINGO! These little gems were everywhere. It appears to be manufactured by Pro MotorCar Products. They don’t sell them directly, but I searched around and found a great price (under $10) at Tool Source ( and ordered a half dozen. I kept my fingers crossed until they arrived. has them, now, too. I could be mistaken, but this one seems improved over the original in that a second glass fiber cartridge is stored in the top of the pen – it’s like getting a second one free! Other than that, they work the same.

The PrepPen is truly one of the most useful widgets in my desk drawer and on my shop bench and really neat. A week does not go by without me reaching for this black and yellow tool because it is just the fastest and easiest way to address any electrical mess. I use it to prepare terminals before soldering and I know my connections are solid. Once I used it to clean up some tiny rock chips on the front of the car. They’d been there awhile and begun to rust. After cleaning with the PrepPen, I suspect the touch-up paint stuck far better. You may wonder why I ordered six? Easy; once I show it to someone, it’s almost impossible not to say, “Here, take it, I’ve got another.”

One caution: The tool uses glass fibers in a brush form to clean objects. Minute glass shards break off during use. They are very, very small. And they are sharp. Eye and skin protection would be prudent. Getting these tiny fragments out of your eye would be a challenge for any emergency room and would seriously mess up your day.

Pro MotorCar Products
1030 Doris Rd.
Auburn Hills, MI 48326

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