I strip them down clean and add a tiny bit of Steve Young’s PBR grease on the teeth and metal parts. Don’t know if it’s needed but it gets a little love to make up for the years of neglect.

I also use a very SMALL amount of grease.
I use Super Lube.
They put grease in this area at the factory when made.

Gottlieb said to use their "black lube" there. I actually ordered a tube of it (1 ounce, but goes a long way) from my Gottlieb distributor back in the day. I'd like to know the hardware-store equivalent product.
.................David Marston

A thin, brown streak of lube was applied originally. This turns into resin, sticking up everything. Greases IMG_1793 (resized).JPGat that time were based on wax, or certain proprietary mixtures with various petroleum derivatives, or later, Polymers. Silicone began to be added to grease in the late 50's, but it was expensive. Most of the early lubes were wax based and as the petroleum distillates dried out turned into a hardening resin.
IMG_1804 (resized).JPGIMG_1810 (resized).JPG

I apply a small amount of Dow Corning 1292 silicone grease to the cog wheel, very small.

Any black lube will contain Graphite, or Molybdenum, The Former is primitive but very effective in certain dry applications, the Latter and exceptional additive for this application. Silicone-based greases containing Flourosilicone or Teflon, as most know it, are the best.

Personally, I don't use any type of liquid or paste type lubricant on EM machines. No matter what the ingredients, any such residual media on stepper teeth, cogs, wheels, levers, bearings, etc. will hold dust & dirt like a sponge and over time turn it into sludge or wax. The main contaminant inside the cabinet and backbox is powdery airborne dust from solenoids and moving parts. Remember why manufacturers recommended grease: to keep these machines running just long enough for the owners to realize their ROI: about 2-3 years. Collectors have different needs. Greases certainly will do the job short term, but eventually you will have to disassemble the mechanisms and remove the stuff. All I ever use on score reels, steppers, etc. is teflon spray which evaporates in seconds and leaves a slippery micro dry powder coating to which nothing sticks. You have to carefully control overspray with rags or paper, but I've never had a problem. I do check these devices every once in a while, and all I find are clean parts with no sludge or waxy buildup.

MBI Instrument Grease for me....