Though I’ve had one or two of these kneadable erasers (aka: putty rubbers) lying around for what seems like forever, it’s only recently that I’ve begun to fall in love with them. Slightly reminiscent of the Silly Putty of our childhood, this slightly sticky, moldable eraser works by absorbing graphite, charcoal, pastel, etc., and does not leave crumbly bits when used.
Have you ever tried one of these?
These erasers are often used in subtractive drawing techniques- a brief tutorial can be found here:
Find something to wrap them in, cling film works. These guys can dry out.