Folks, I have NO knowledge of whether this is true or not.

https://archive.org/details/micro-cornucopia-magazine-1985-08/page/n12/mode/1up

S-100 Toolbox by Dave Hardy

Like all bus-oriented, plug-in systems, S-100 boards and frames have
connectors that sometimes get dirty. In fact, about 50 percent of all of
the S-100 problems I have had in the last 10 years have been because of
dirty edge connectors on S-100 boards, or damaged sockets in an S-100 frame.

There's not much you can do about a bad socket (except replace it), but
edge connectors can be cleaned with some isopropyl alcohol and a rag.
Because the pads on most edge connectors are plated with a few mils of
gold, it is not a good idea to simply rub off the dirt and tarnish with
an eraser.

Having been the victim of bad edge connectors that had been erased by
well meaning users, even the idea of using a pencil eraser on a
gold-plated connector used to make me cringe, not only because of the
damage to the gold plating, but also because of the oily residue left
behind by the eraser.

But about a year ago, I discovered that one eraser, the Mars Staedtler
Rasor 52730, not only cleans the connector without damage to the gold
plating, but also leaves no residue.

Since that time, I have used the Mars eraser with excellent results, and
have decided to make it a permanent resident in my S-100 toolbox.

https://web.archive.org/web/20101230211113/http://staedtler.com/Mars_rasor_gb.Staedtler

Researching

Louis Ohland wrote:
> Mars Staedtler Rasor 52730

On Sunday, July 30, 2023 at 6:36:33 PM UTC-4, Louis Ohland wrote:
> > Mars Staedtler Rasor 52730

Those white erasers were "the standard" for drafting work, as they erased cleanly. However, there's really no "magic" in that particular model, there were other white erasers that worked just as well, a common one being the Eberhard Faber "Magic Rub" 1954.

I was unable to find the 527 30 with IA, but that comment was from 1985,
IIRC. Just trying to ID the composition of the eraser.

RickE wrote:
> On Sunday, July 30, 2023 at 6:36:33 PM UTC-4, Louis Ohland wrote:
>>> Mars Staedtler Rasor 52730
>
> Those white erasers were "the standard" for drafting work, as they erased cleanly. However, there's really no "magic" in that particular model, there were other white erasers that worked just as well, a common one being the Eberhard Faber "Magic Rub" 1954.
>

https://cool.culturalheritage.org/byorg/abbey/an/an25/an25-5/an25-504.html

Louis Ohland wrote:
> I was unable to find the 527 30 with IA, but that comment was from 1985,
> IIRC. Just trying to ID the composition of the eraser.
>
> RickE wrote:
>> On Sunday, July 30, 2023 at 6:36:33 PM UTC-4, Louis Ohland wrote:
>>>> Mars Staedtler Rasor 52730
>>
>> Those white erasers were "the standard" for drafting work, as they
>> erased cleanly.  However, there's really no "magic" in that particular
>> model, there were other white erasers that worked just as well, a
>> common one being the Eberhard Faber "Magic Rub" 1954.
>>

"Magic Rub" 1954 is still around, look for either Sanford -OR-
Prismacolor 70503. Many art and craft stores sell them.

Louis Ohland wrote:
> https://cool.culturalheritage.org/byorg/abbey/an/an25/an25-5/an25-504.html
>
> Louis Ohland wrote:
>> I was unable to find the 527 30 with IA, but that comment was from
>> 1985, IIRC. Just trying to ID the composition of the eraser.
>>
>> RickE wrote:
>>> On Sunday, July 30, 2023 at 6:36:33 PM UTC-4, Louis Ohland wrote:
>>>>> Mars Staedtler Rasor 52730
>>>
>>> Those white erasers were "the standard" for drafting work, as they
>>> erased cleanly.  However, there's really no "magic" in that
>>> particular model, there were other white erasers that worked just as
>>> well, a common one being the Eberhard Faber "Magic Rub" 1954.
>>>

https://archive.org/details/sim_reprographics-design-imaging_1970-08_43_8/page/4/mode/1up

J.S. Staedtler is providing 527 30 Mars-Rasor technical erasers that are
identical in texture to the familiar block-form 526 50 Mars-Plastic...

Louis Ohland wrote:
> Staedtler Rasor 52730

The holder is 527-30, the bone-white color refill is 527-35 [graphite].
Refill 527-40 is for ink.

Louis Ohland wrote:
> I was unable to find the 527 30 with IA, but that comment was from 1985,
> IIRC. Just trying to ID the composition of the eraser.
>
> RickE wrote:
>> On Sunday, July 30, 2023 at 6:36:33 PM UTC-4, Louis Ohland wrote:
>>>> Mars Staedtler Rasor 52730
>>
>> Those white erasers were "the standard" for drafting work, as they
>> erased cleanly.  However, there's really no "magic" in that particular
>> model, there were other white erasers that worked just as well, a
>> common one being the Eberhard Faber "Magic Rub" 1954.
>>

On Sun, 30 Jul 2023 17:37:14 -0500, Louis Ohland <ohland@charter.net>
wrote:

>https://web.archive.org/web/20101230211113/http://staedtler.com/Mars_rasor_gb.Staedtler
>
>Researching
>
>Louis Ohland wrote:
>> Mars Staedtler Rasor 52730

They make something called Stabilant 55 that you mix with 100%
isopropanol and it does a great job of cleaning and improving
connections without taking the plating off.
IBM told us to never use an eraser on a gold contact. We used IBM
Cleaning fluid (Trichloroethane 1.1.1)

> They make something called Stabilant 55 that you mix with 100%
> isopropanol and it does a great job of cleaning and improving
> connections without taking the plating off.
> IBM told us to never use an eraser on a gold contact. We used IBM
> Cleaning fluid (Trichloroethane 1.1.1)

Trichloroethane is some nasty stuff, however - "DeoxIT" is a good, modern product to use.

On Mon, 31 Jul 2023 11:34:11 -0700 (PDT), IBMMuseum
<ibmmuseum@gmail.com> wrote:

>> They make something called Stabilant 55 that you mix with 100%
>> isopropanol and it does a great job of cleaning and improving
>> connections without taking the plating off.
>> IBM told us to never use an eraser on a gold contact. We used IBM
>> Cleaning fluid (Trichloroethane 1.1.1)
>
>Trichloroethane is some nasty stuff, however - "DeoxIT" is a good, modern product to use.

Yeah after 25 years,, they took the "gold can" away from us. The old
guys said it was safer than carbon tetrachloride that they used before
;)

We were always using the gold can, for just about everything and we
ain't dead yet.

On Monday, July 31, 2023 at 11:23:57 PM UTC-4, gfre...@aol.com wrote:

> Yeah after 25 years,, they took the "gold can" away from us. The old
> guys said it was safer than carbon tetrachloride that they used before
> ;)

I used "carbon tet" for many things back in the 1960s, it was a great cleaner. But as a demonstration of how dangerous it could be in closed spaces, I used to kill butterflies for my collection using an old peanut butter jar (yes, they used to be made out of glass with metal lids). Put a few drops on a tissue, put the tissue in the jar then add a thin cardboard circle to cover the tissue, put in the butterfly and screw down the lid. Within 10 seconds the butterfly would be dead, and it died so quickly that it didn't have a chance to injure itself. The "typical" butterfly killing chemical, nail polish remover, took much longer to work, the butterflies would beat themselves inside the jar and far too often you wound up with a specimen that wasn't worthy of mounting to the butterfly board. Triclor was indeed safer (and less effective as a cleaner), though it certainly needed to be used with care. Isopropyl alcohol is even safer, way less effective as a cleaner, but has not yet fallen completely afoul with the safety police.