Just Scraping By . . .
This was a hopeful chain submitted by an A.S. member. Covered in gunk, it cleaned up to be Poulan branded chain with limited use on the cutters.
Hard to see, unless in good light (and hard to photograph - sorry), but
every cutter on the loop was abraded on the top
and side plate, in a smooth, almost polished manner (see color and reflection differences in photos), essentially creating reverse bevels. In other words, the cutting edges were now angled away from the wood fibers.
I was not present when this occurred, but I assume that it was not a misguided attempt at sharpening. Although, it is more common to see abrasions on the top plate only, or predominantly on one side, when accidentally hitting a rock. This user must have tried to power through something really abrasive, like cement board?
Can it be saved? Yes - by grinding back almost 1/2 of each tooth, creating an
end-of-life chain (note that some cutters were abraded back farther than those shown). That's a lot of work for a small return.
Thought about lowering the depth gauges significantly, to allow the cutters to rotate back father, which might allow the bevel to 'bite', but that would not help the abraded side plates cut the walls of the kerf.
WINNER? The rock, brick, or whatever the chain hit.
LESSONS? Look before you cut! If you hit something - STOP!
Philbert
Reminds me of my first grinding experiences with the Stihl 180 were the chain ripped due to only a slight cut into the rivet area. 
