Most of my DPCB (desktop printed circuit board) burnishing problems all have one cause: impatience. Some things just should not be rushed.
Here is a little test board. It is just 2 x 3 inches. I print these for practice and testing. (If you would like the gerber file, just comment below.)
Now we burnish this board. This photograph illustrates what happened when I used 3M Scotchbrite Heavy Duty scouring pad, too much pressure, and too much time.
We can see that this bad burnishing removed bits of pads. There is a broken trace.
Producing good Desktop Printed Circuit Boards requires patience.