There’s nothing quite like genuine parts when you’re doing a little refurbishing. These 1282 replacement erasers for the clamp, originally made from the Red Ruby formula, are still surprisingly pliant.
They were used for the earlier Blackwing and Van Dyke pencils.
Eventually the Blackwing shared the same eraser as the Microtomic (which was once the Van Dyke), and were similar to the Pink Pearl.
These remain remarkably soft as well:
Though to be honest neither were very good at erasing, even during their heyday.
If the pencil had a softer lead, and if you were writing on smooth paper, the eraser tended to distribute the graphite more than erase it.
Still, it’s better to have a fresh replacement than a hardened and shriveled eraser—something you often find on vintage Blackwing 602 and Van Dyke 601 pencils.