How to remove Sorbothane feet stacking marks.

So over the years I’ve tried rubbing alcohol, lighter fluid, along with glass cleaners. They all minimize the marks to some degree, but still leave a shadow of evidence that something was stacked atop a piece of gear. Sorbothane is nasty and leaves like a oily mark which almost seems like it’s penetrated below the paint, powder coat, or anodized surface.

Eureka as I just discovered treating oil with oil works!

A drop of Mineral Oil on each Sorbothane mark rubbed in a circular motion and then left to sit for an hour works. You wipe off the access oil with a paper towel and then fully de-grease the area with Windex.

Once finished the Sorbothane mark is completely gone with no shadowing.

So now that piece of as new condition gear you had to list at less than mint due to these marks once is again truly perfect :)
Cutting a small piece of paper to fit under the foot would probably eliminate the drama of running through a regimen of cleaners.
Instructions that come with the sorbothane products mention a clear coat that prevents the residue from leaving difficult to remove marks. A simpler solution is clear plastic sandwich wrap. 
Another product marketed for vibration absorption is the blocks of cork sandwiched between layers of ribbed black rubber. Those also will stain any finish you put them on. They left permanent marks on my clear maple flooring and the stain seemed to have gone through the varnish into the wood itself. Even refinishing the floor didn't completely remove them.
Those cork and rubber blocks are much cheaper to buy from a plumbing supply store; they are designed to go under water heaters. 
Actually the Rubber/Cork squares are used on wooden pallets while trucks are transposing HVAC equipment. As are the Rubber/Blue Foam ones.