I have a ball bowler with stepper units and score reels and I used rubbing alcohol with q tips and cotton balls to clean. Than I put super lube synthetic grease which I bought at the hardware store on just the metal to metal parts. The nylon to metal or nylon to nylon parts do not need lubricating. I believe you can use lighter fluid form lighters instead of alcohol which can be bought at walgreens stores. Hope this helps!

Here is a pinside discussion from 10 months ago that should help you with your question.

http://pinside.com/pinball/forum/topic/cleaning-stepper-units

I use Mean Green with a Scotchbrite Pad followed with a 90% Alcohol wipe down with a paper towel for all Steppers.

I then use a few drops of Teflon Oil on the metal gears and very thin layer Teflon Lube Gel on the Stepper Unit PCB Disc. This all per Clay's Video. Fantastic safe results.

If the unit still does not advance decrement as it should I check all the Springs and sometimes have to cut one down a bit to get the original tension back. You can replace the Springs as well but if you are careful cutting back a few rungs it is easy enough and does not distort the Spring.

Ken

Rip em apart and put em in the ultra sound

Clean the rivets with scotch bright pads and teflon lube them after
https://plus.google.com/u/0/photos/112945653847568274013/albums/5643156154506693633

--Jeff

On woodrails I use an old toothbrush with some Mean Green sprayed on the bristles. It lets you get between the two surfaces without taking anything apart. It doesn't do a perfect job, but at least you'll get rid of the old grease and crud quickly and easily.

WD40

.... Just kidding. Don't do that.

I buy boxes of those alcohol pads. They seem to cut the gunk pretty freely and they are kind of handy. An ultrasonic cleaner would be the cat's pajamas…maybe someday.

Ditto to Way2wyrd's tip. Strip up apart (take a picture to help your memory if you are me) wash them in the ultrasonic cleaner and rebuild them. Clean the rivets with scotch bright pads or what you got and teflon lube them after reassembly.

Good as new and work perfect with possibly a new spring kit from PBR.

Dinosaur approved. Nice pictorial.