Digital BW, The Print

I've used a sharpened soft lead pencil to good effect for small spots 
on inkjet BW prints. The key is to rub the spot with your clean 
finger when you're done and the pencil lead blends in and disappears. 
I've also used an eraser to lightly remove too much lead I might have 
put down, and it works -- must be gentle though, and use a soft 
eraser.