As I mentioned in the article, yes, some erasers are more liable to leave perceptible scuff marks, but on the other hand, some won't. The Papermate one I used first, quickly and easily removed a large amount of black marks, but did leave some light scuffing behind. As far as I could tell, the softer "kneadable rubber" eraser did not leave scuff marks on the three or four covers I tried it on.
I'm not sure, but I'm now thinking that the black 'soiling' on the Pink Floyd cover may actually have come from that album being pressed against and rubbing on the back of the dark colored
Animals album for 25-30 years, as the backside of my Animals cover has what almost looks like a mirror image of the marring found on the Wish You Were Here cover, only it has the ink worn off and the white showing through. I'm thinking it could be ink residue that had bonded with the white cover and in a case like that you are not necessarily rubbing away the original surface of the cover with the eraser, but only the undesired layer of (ink?) residue (provided you use a non-abrasive eraser). Now that I keep both of those records in poly sleeves, I think the white cover might not get that buildup on it again.
Also, you are removing what is likely decades of buildup and I don't think the cleaned covers are going to get soiled looking like that again anytime real soon. Everything begins getting dirty again after it is cleaned, so should we never clean anything?
Even with the light scuffing from using the more abrasive eraser first, I am still way more happy with how that Pink Floyd record looks now. If you could put the 'before' and 'after' versions next to each other and were trying to sell them or just asking someone to pick one for free, I am confident the 'after' version would be selected every time. Maybe it's not a worthwhile thing to do with every slightly tarnished cover, but in many cases, I think the benefits will greatly outweigh any possible negatives - particularly if you deal with a lot of inexpensive yard sale/thrift store records that you just want to look nice again.
Thanks for checking out the article. I'm not trying to hard sell anyone on the idea or anything (despite my wordy reply here

), and I'm sure results will vary depending on the type of soiling/marks, the cover surface, and the eraser. Do whatever you are comfortable with. I am just sharing a technique/process that I do think is worthwhile.