The sad this is I just got done spotting prints for class. Freestyle also sells a sheet of spotting dyes that works fine. The recommendation about the 5/0 brush is a good one. Make sure to "spot" not brush the imperfection. Also like mentioned let it dry before dabbing more dye. Another recommendation that I found is a little goes a long way. Don't try to do the whole picture in one sitting. Yes it is a pain and frustrating but you will get over it One last item, block your print with a piece of white paper so you can use the paper to get your tint/tone to where you need it to be before applying it to your print. Match it then apply it. Like Louie said "the objective is to reduce local contrast so that the bright white spot doesn't stand out".