used Millions of erasers over the course of my art career but I've
finally whittled my choices down to 2 kinds.
A) Kneaded Eraser:
This eraser usually comes as a plain Grey or Blue square. Once you
open it from it's wrapping you start working it like silly putty.
Squeezing it into a Ball...pulling it into a ribbon..folding it, squishing
it..Kneading it, really. What's the purpose? Well, you can squeeze
it down into a fine point and erase lines in hard to reach places
without disturbing the pencil lines around it. Another handy feature
is that it doesn't completly erase lines...If you just dab the eraser
over the lines you can lighten them up for inking.