It is not uncommon for artists working with dry media to use excessive pressure and friction when developing a drawing. As such, they may find the paper/sizing “breached” which often results in a significant number of raised fibers as well as a diminishment to the paper’s integrity. Sometimes, they may find that the paper’s tooth has become “burnished.” The burnish will make it very difficult to add any additional material as the surface tends to act more like wax paper then an appropriate drawing paper. One way to deal with a burnish is to carefully create a new tooth with sandpaper. Be aware though that this approach is actually an attempt to contend with a burnish by making an intentional breach. Thus, you will be likely to find some increase in noticeable paper fiber with this approach.
WARNING: This method of contending with a burnish is a “last resort procedure.” It is not something that should become part of your normal drawing process. This measure can SERIOUSLY damage your drawing/paper if you are not EXTREMELY careful. Please be extremely mindful of your pressure when trying this. We also highly recommend that you practice/experiment with this on a practice effort before attempting g this on any actual drawing.
Here you can see an area of an exercise that will not take any more material due to a burnish. With some careful use with a FLAT piece of sandpaper, a new tooth will emerge that is capable of accepting material.
Additional note: while the video states that this is a 320 grit–you can use something slightly rougher but I would not recommend anything rougher than 180 under any circumstances.