emery sticks

They're a little abrasive. I always used a "penny wrapper" (actually, quarter wrapper) when servicing pinball machines -- if you keep up with it, regularly, before contacts get too pitted, etc.

It's coarse enough that it can remove surface oxidation without removing the metal.

SoftScrub on a wet paper towel is fabulous. You get an optical finish and all the dust washes away.

John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics

For small signal elecrical contacts, alcohol on kraft paper is often enough.

For applications where flexibility isn't your friend, these sticks provide a narrow, stiff, penetrating 'sanding block' function, with a gross remote indication of attack angle at the contact surface.

There are two 'grits' offered on each stick, the finest of which rivals T-0 lubricated papers.

RL

I have an old burnishing tool with replaceable strips, works great. Does not seem to be made anymore.

Cheers

Here is something similar

Pinball machines most often have "coil current" flowing through contacts. Sometimes lamp current. And, see lots of cycles.

If you keep on top of them, the "penny wrapper" works great as it just removes surface oxidization. The paper is a lot rougher than kraft paper. Yet, reasonably soft -- a pitted contact will be evident in the damage it does to the *paper* (which will have little effect on the pit!).

Because the wrappers are tubes, you have two layers to give you added thickness.

I used to carry a burnishing tool but found the wrappers much more convenient -- if you're working a Route, you likely have 100 of them on hand to collect the "take". It's much easier to roll it at each location so you get an accurate count -- usually split with the location owner -- as well as being able to carry it easier ($1000 in quarters weighs quite a bit!)

You can "roll" (curl) the penny wrapper around your index finger to give it added stiffness, as needed. Your finger then dictates how you are approaching the contact(s).

As most contact pairs are on long leafs in a pinball machine, you can usually slip the paper between them and gentle hold the "points" together while removing the wrapper. This gives a wipe to each contact as both sides of the wrapper are identical.

Unlike "electronic equipment", having to replace a set of contacts in a pinball machine (or other arcade piece) is tedious as everything is soldered in and the smallest removable assembly is a couple of cubic feet.

You *really* want to take care of a machine lest you end up spending a *day* on a preventable repair! (during which time, the machine isn't earning you any money)

SoftScrub has little plastic particles that replace the crushed silica or feldspar of ordinary clensers, so it ought to be useful.

I'd add that the paper from which ordinary coffee filters are made is just the right roughness and strength for such applications.

Joe

SoftScrub is great for polishing copperclad, especially ENIG.

John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics